diff --git a/examples/gno.land/p/demo/ufmt/ufmt.gno b/examples/gno.land/p/demo/ufmt/ufmt.gno
index 0e6143d6ebd..3820e53169f 100644
--- a/examples/gno.land/p/demo/ufmt/ufmt.gno
+++ b/examples/gno.land/p/demo/ufmt/ufmt.gno
@@ -57,6 +57,8 @@ func Sprintf(format string, args ...interface{}) string {
 				buf += v.String()
 			case string:
 				buf += v
+			case bigint:
+				buf += string(v)
 			default:
 				buf += "(unhandled)"
 			}
@@ -70,6 +72,8 @@ func Sprintf(format string, args ...interface{}) string {
 				buf += strconv.FormatUint(uint64(v), 10)
 			case uint64:
 				buf += strconv.FormatUint(v, 10)
+			case bigint:
+				buf += string(v)
 			default:
 				buf += "(unhandled)"
 			}
diff --git a/examples/gno.land/p/demo/ufmt/ufmt_test.gno b/examples/gno.land/p/demo/ufmt/ufmt_test.gno
index 07ba76c55b0..638adaa7129 100644
--- a/examples/gno.land/p/demo/ufmt/ufmt_test.gno
+++ b/examples/gno.land/p/demo/ufmt/ufmt_test.gno
@@ -24,6 +24,7 @@ func TestSprintf(t *testing.T) {
 		{"uint [%d]", []interface{}{uint(42)}, "uint [42]"},
 		{"int64 [%d]", []interface{}{int64(42)}, "int64 [42]"},
 		{"uint64 [%d]", []interface{}{uint64(42)}, "uint64 [42]"},
+		{"bigint [%d]", []interface{}{bigint(42)}, "bigint [42]"}
 		{"bool [%t]", []interface{}{true}, "bool [true]"},
 		{"bool [%t]", []interface{}{false}, "bool [false]"},
 		{"invalid bool [%t]", []interface{}{"invalid"}, "invalid bool [(unhandled)]"},
diff --git a/gno.land/pkg/sdk/vm/convert.go b/gno.land/pkg/sdk/vm/convert.go
index de4db67fb04..b6c41bfd235 100644
--- a/gno.land/pkg/sdk/vm/convert.go
+++ b/gno.land/pkg/sdk/vm/convert.go
@@ -3,6 +3,7 @@ package vm
 import (
 	"encoding/base64"
 	"fmt"
+	"math/big"
 	"strconv"
 
 	gno "github.com/gnolang/gno/gnovm/pkg/gnolang"
@@ -153,6 +154,18 @@ func convertArgToGno(arg string, argT gno.Type) (tv gno.TypedValue) {
 			}
 			tv.SetUint64(u64)
 			return
+		case gno.BigintType:
+			if arg[0] == '+' {
+				panic("numbers cannot start with +")
+			}
+			bi, ok := big.NewInt(0).SetString(arg, 10)
+			if !ok {
+				panic(fmt.Sprintf(
+					"error parsing bigint %v", arg))
+			}
+
+			tv.SetBigInt(bi)
+			return
 		default:
 			panic(fmt.Sprintf("unexpected primitive type %s", bt.String()))
 		}
diff --git a/gnovm/pkg/gnolang/gonative.go b/gnovm/pkg/gnolang/gonative.go
index 69e468f755a..ba2dd33e22e 100644
--- a/gnovm/pkg/gnolang/gonative.go
+++ b/gnovm/pkg/gnolang/gonative.go
@@ -2,6 +2,7 @@ package gnolang
 
 import (
 	"fmt"
+	"math/big"
 	"reflect"
 )
 
@@ -508,7 +509,9 @@ func go2GnoValueUpdate(alloc *Allocator, rlm *Realm, lvl int, tv *TypedValue, rv
 			tv.SetFloat64(rv.Float())
 		}
 	case BigintKind:
-		panic("not yet implemented")
+		if lvl != 0 {
+			tv.SetBigInt(rv.Interface().(*big.Int))
+		}
 	case BigdecKind:
 		panic("not yet implemented")
 	case ArrayKind:
@@ -828,7 +831,7 @@ func gno2GoType(t Type) reflect.Type {
 		case Float64Type:
 			return reflect.TypeOf(float64(0))
 		case BigintType, UntypedBigintType:
-			panic("not yet implemented")
+			return reflect.TypeOf(big.NewInt(0))
 		case BigdecType, UntypedBigdecType:
 			panic("not yet implemented")
 		default:
@@ -1113,6 +1116,8 @@ func gno2GoValue(tv *TypedValue, rv reflect.Value) (ret reflect.Value) {
 			rv.SetFloat(float64(tv.GetFloat32()))
 		case Float64Type:
 			rv.SetFloat(tv.GetFloat64())
+		case BigintType, UntypedBigintType:
+			rv.Set(reflect.ValueOf(tv.GetBigInt()))
 		default:
 			panic(fmt.Sprintf(
 				"unexpected type %s",
diff --git a/gnovm/pkg/gnolang/op_binary.go b/gnovm/pkg/gnolang/op_binary.go
index 13156133e38..f6606567b83 100644
--- a/gnovm/pkg/gnolang/op_binary.go
+++ b/gnovm/pkg/gnolang/op_binary.go
@@ -1109,9 +1109,9 @@ func shlAssign(lv, rv *TypedValue) {
 	case Uint64Type:
 		lv.SetUint64(lv.GetUint64() << rv.GetUint())
 	case BigintType, UntypedBigintType:
-		lb := lv.GetBigInt()
-		lb = big.NewInt(0).Lsh(lb, rv.GetUint())
-		lv.V = BigintValue{V: lb}
+		z := big.NewInt(0)
+		z.Lsh(lv.GetBigInt(), rv.GetUint())
+		lv.V = BigintValue{V: z}
 	default:
 		panic(fmt.Sprintf(
 			"operators << and <<= not defined for %s",
diff --git a/gnovm/pkg/gnolang/op_inc_dec.go b/gnovm/pkg/gnolang/op_inc_dec.go
index 80987707035..e0763eeaf02 100644
--- a/gnovm/pkg/gnolang/op_inc_dec.go
+++ b/gnovm/pkg/gnolang/op_inc_dec.go
@@ -1,5 +1,7 @@
 package gnolang
 
+import "math/big"
+
 func (m *Machine) doOpInc() {
 	s := m.PopStmt().(*IncDecStmt)
 
@@ -42,6 +44,8 @@ func (m *Machine) doOpInc() {
 		lv.SetUint32(lv.GetUint32() + 1)
 	case Uint64Type:
 		lv.SetUint64(lv.GetUint64() + 1)
+	case BigintType:
+		lv.GetBigInt().Add(lv.GetBigInt(), big.NewInt(1))
 	default:
 		panic("unexpected type in in operation")
 	}
@@ -94,6 +98,8 @@ func (m *Machine) doOpDec() {
 		lv.SetUint32(lv.GetUint32() - 1)
 	case Uint64Type:
 		lv.SetUint64(lv.GetUint64() - 1)
+	case BigintType:
+		lv.GetBigInt().Sub(lv.GetBigInt(), big.NewInt(1))
 	default:
 		panic("unexpected type in in operation")
 	}
diff --git a/gnovm/pkg/gnolang/values.go b/gnovm/pkg/gnolang/values.go
index 3de74ac0130..24521cc31f8 100644
--- a/gnovm/pkg/gnolang/values.go
+++ b/gnovm/pkg/gnolang/values.go
@@ -987,6 +987,7 @@ func (tv TypedValue) Copy(alloc *Allocator) (cp TypedValue) {
 	case BigintValue:
 		cp.T = tv.T
 		cp.V = cv.Copy(alloc)
+		cp.N = tv.N
 	case *ArrayValue:
 		cp.T = tv.T
 		cp.V = cv.Copy(alloc)
@@ -1423,6 +1424,17 @@ func (tv *TypedValue) GetFloat64() float64 {
 	return *(*float64)(unsafe.Pointer(&tv.N))
 }
 
+func (tv *TypedValue) SetBigInt(bi *big.Int) {
+	if debug {
+		if tv.T.Kind() != BigintKind || isNative(tv.T) {
+			panic(fmt.Sprintf(
+				"TypedValue.SetBigInt() on type %s",
+				tv.T.String()))
+		}
+	}
+	tv.V = BigintValue{bi}
+}
+
 func (tv *TypedValue) GetBigInt() *big.Int {
 	if debug {
 		if tv.T != nil && tv.T.Kind() != BigintKind {
@@ -2430,6 +2442,10 @@ func defaultValue(alloc *Allocator, t Type) Value {
 			)
 		}
 	default:
+		switch t.Kind() {
+		case BigintKind:
+			return BigintValue{V: big.NewInt(0)}
+		}
 		return nil
 	}
 }
diff --git a/gnovm/pkg/gnolang/values_conversions.go b/gnovm/pkg/gnolang/values_conversions.go
index 9fc2ce4a567..1efc83c0719 100644
--- a/gnovm/pkg/gnolang/values_conversions.go
+++ b/gnovm/pkg/gnolang/values_conversions.go
@@ -138,6 +138,9 @@ GNO_CASE:
 			x := float64(tv.GetInt()) // XXX determinism?
 			tv.T = t
 			tv.SetFloat64(x)
+		case BigintKind:
+			tv.V = BigintValue{V: big.NewInt(tv.GetInt64())}
+			tv.T = t
 		case StringKind:
 			tv.V = alloc.NewString(string(rune(tv.GetInt())))
 			tv.T = t
@@ -315,6 +318,9 @@ GNO_CASE:
 			x := float64(tv.GetInt32()) // XXX determinism?
 			tv.T = t
 			tv.SetFloat64(x)
+		case BigintKind:
+			tv.V = BigintValue{V: big.NewInt(tv.GetInt64())}
+			tv.T = t
 		case StringKind:
 			tv.V = alloc.NewString(string(tv.GetInt32()))
 			tv.T = t
@@ -374,6 +380,9 @@ GNO_CASE:
 			x := float64(tv.GetInt64()) // XXX determinism?
 			tv.T = t
 			tv.SetFloat64(x)
+		case BigintKind:
+			tv.V = BigintValue{V: big.NewInt(tv.GetInt64())}
+			tv.T = t
 		case StringKind:
 			tv.V = alloc.NewString(string(rune(tv.GetInt64())))
 			tv.T = t
@@ -433,6 +442,9 @@ GNO_CASE:
 			x := float64(tv.GetUint()) // XXX determinism?
 			tv.T = t
 			tv.SetFloat64(x)
+		case BigintKind:
+			tv.V = BigintValue{V: big.NewInt(tv.GetInt64())}
+			tv.T = t
 		case StringKind:
 			tv.V = alloc.NewString(string(rune(tv.GetUint())))
 			tv.T = t
@@ -669,6 +681,9 @@ GNO_CASE:
 			x := float64(tv.GetUint64()) // XXX determinism?
 			tv.T = t
 			tv.SetFloat64(x)
+		case BigintKind:
+			tv.V = BigintValue{V: big.NewInt(tv.GetInt64())}
+			tv.T = t
 		case StringKind:
 			tv.V = alloc.NewString(string(rune(tv.GetUint64())))
 			tv.T = t
@@ -788,6 +803,41 @@ GNO_CASE:
 				"cannot convert %s to %s",
 				tvk.String(), k.String()))
 		}
+	case BigintKind:
+		switch k {
+		case IntKind, Int8Kind, Int16Kind, Int32Kind, UintKind, Uint8Kind, Uint16Kind, Uint32Kind:
+			panic(fmt.Sprintf(
+				"cannot convert %s to %s",
+				tvk.String(), k.String()))
+		case Int64Kind:
+			x := tv.GetBigInt()
+			if x.IsInt64() {
+				tv.T = t
+				tv.SetInt64(x.Int64())
+			} else {
+				panic(fmt.Sprintf(
+					"cannot convert %s to %s",
+					tvk.String(), k.String()))
+			}
+		case Uint64Kind:
+			x := tv.GetBigInt()
+			if x.IsUint64() {
+				tv.T = t
+				tv.SetUint64(x.Uint64())
+			} else {
+				panic(fmt.Sprintf(
+					"cannot convert %s to %s",
+					tvk.String(), k.String()))
+			}
+		case StringKind:
+			tv.T = t
+			tv.SetString(StringValue(tv.GetBigInt().String()))
+		default:
+			panic(fmt.Sprintf(
+				"cannot convert %s to %s",
+				tvk.String(), k.String()))
+
+		}
 	case StringKind:
 		bt := baseOf(t)
 		switch cbt := bt.(type) {
@@ -809,6 +859,20 @@ GNO_CASE:
 					"cannot convert %s to %s",
 					tvk.String(), t.String()))
 			}
+		case PrimitiveType:
+			switch k {
+			case BigintKind:
+				bi := new(big.Int)
+				bi, ok := bi.SetString(tv.GetString(), 10)
+				if !ok {
+					panic(fmt.Sprintf(
+						"cannot convert %s to %s",
+						tvk.String(), k.String(),
+					))
+				}
+				tv.V = BigintValue{V: bi}
+				tv.T = t
+			}
 		default:
 			panic(fmt.Sprintf(
 				"cannot convert %s to %s",
diff --git a/gnovm/tests/files/type40.gno b/gnovm/tests/files/type40.gno
new file mode 100644
index 00000000000..c76b208a923
--- /dev/null
+++ b/gnovm/tests/files/type40.gno
@@ -0,0 +1,61 @@
+package main
+
+var (
+	mi64  int64  = 123
+	mui64 uint64 = 123
+
+	mbi bigint = 123
+
+	max_uint64_plus_1 bigint = 18446744073709551616
+	max_int64_plus_1  bigint = 9223372036854775808
+)
+
+func main() {
+	// default value
+	var _zeroBig bigint
+	shouldEQ(_zeroBig, bigint(0))
+
+	// int64 > bigint
+	shouldEQ(bigint(mi64), mbi)
+
+	// uint64 > bigint
+	shouldEQ(bigint(mui64), mbi)
+
+	// bigint > int64
+	shouldEQ(int64(mbi), mi64)
+
+	// bigint(too big) > int64
+	// int64(max_int64_plus_1) // cannot convert BigintKind to Int64Kin
+
+	// bigint > uint64
+	shouldEQ(uint64(mbi), mui64)
+
+	// bigint(too big) > uint64
+	// uint64(max_uint64_plus_1) // cannot convert BigintKind to Int64Kind
+
+	// OpInc, OpDec
+	var _oneBig bigint = 1
+	_oneBig++
+	shouldEQ(_oneBig, bigint(2))
+
+	_oneBig--
+	shouldEQ(_oneBig, bigint(1))
+}
+
+func shouldEQ(a, b interface{}) bool {
+	if a == b {
+		println("true")
+	} else {
+		println("false")
+	}
+	return a == b
+}
+
+// Output:
+// true
+// true
+// true
+// true
+// true
+// true
+// true