diff --git a/osiris/cairo/serde/deserialize.py b/osiris/cairo/serde/deserialize.py
index f7158e7..ec7cd41 100644
--- a/osiris/cairo/serde/deserialize.py
+++ b/osiris/cairo/serde/deserialize.py
@@ -1,3 +1,5 @@
+import re
+
 import numpy as np
 
 from osiris.cairo.serde.utils import felt_to_int, from_fp
@@ -17,6 +19,9 @@ def deserializer(serialized, dtype):
     elif dtype.startswith('Tensor<'):
         return deserialize_tensor(serialized, dtype)
 
+    elif dtype.startswith('MutMatrix<'):
+        return deserialize_matrix(serialized, dtype)
+
     elif dtype.startswith('('):  # Tuple
         return deserialize_tuple(serialized, dtype)
 
@@ -27,7 +32,7 @@ def deserializer(serialized, dtype):
 def deserialize_fp(serialized):
     parts = serialized.split()
     value = from_fp(int(parts[0]))
-    if len(parts) > 1 and parts[1] == '1':  # Check for negative sign
+    if len(parts) > 1 and parts[1] == 'true':  # Check for negative sign
         value = -value
     return value
 
@@ -60,24 +65,56 @@ def deserialize_tensor(serialized, dtype):
 
 def deserialize_tuple(serialized, dtype):
     types = dtype[1:-1].split(', ')
-    if 'Tensor' in types[0]:
-        tensor_end = find_nth_occurrence(serialized, ']', 2)
-        depth = 1
-        for i in range(tensor_end, len(serialized)):
-            if serialized[i] == '[':
-                depth += 1
-            elif serialized[i] == ']':
-                depth -= 1
-                if depth == 0:
-                    tensor_end = i + 1
-                    break
-        part1 = deserializer(serialized[:tensor_end].strip(), types[0])
-        part2 = deserializer(serialized[tensor_end:].strip(), types[1])
-    else:
-        split_index = serialized.find(']') + 2
+    # Check if there is no space between span and matrix.
+    is_no_space = re.search(r']\{', serialized)
+    if is_no_space:
+        split_index = is_no_space.start() + 1
         part1 = deserializer(serialized[:split_index].strip(), types[0])
         part2 = deserializer(serialized[split_index:].strip(), types[1])
-    return part1, part2
+        return part1, part2
+    else:
+        if 'Tensor' in types[0]:
+            tensor_end = find_nth_occurrence(serialized, ']', 2)
+            depth = 1
+            for i in range(tensor_end, len(serialized)):
+                if serialized[i] == '[':
+                    depth += 1
+                elif serialized[i] == ']':
+                    depth -= 1
+                    if depth == 0:
+                        tensor_end = i + 1
+                        break
+            part1 = deserializer(serialized[:tensor_end].strip(), types[0])
+            part2 = deserializer(serialized[tensor_end:].strip(), types[1])
+        else:
+            split_index = serialized.find(']') + 2
+            part1 = deserializer(serialized[:split_index].strip(), types[0])
+            part2 = deserializer(serialized[split_index:].strip(), types[1])
+        return part1, part2
+
+
+def deserialize_matrix(serialized, dtype):
+
+    # Extract inner dtype
+    pattern = r"<(.*)>"
+    inner_dtype = re.search(pattern, dtype).group(1)
+
+    # Extract the matrix content and shape from the serialized string
+    content, shape_str = serialized.split("} ")
+    # Last two numbers are the shape
+    shape = tuple(map(int, shape_str.split()[-2:]))
+
+    # Use regex to find all occurrences of ': ' followed by any characters until the next ' :' or end of string
+    pattern = r': (.*?)(?=\s\d+: |$)'
+    elements = re.findall(pattern, content)
+
+    # Deserialize each element using the appropriate deserializer based on dtype
+    deserialized_elements = [deserializer(
+        element, inner_dtype) for element in elements]
+
+    # Reshape the deserialized elements into a numpy array of the specified shape
+    matrix = np.array(deserialized_elements).reshape(shape)
+    return matrix
 
 
 def find_nth_occurrence(string, sub_string, n):
diff --git a/tests/test_deserialize.py b/tests/test_deserialize.py
index e78502e..ae53c45 100644
--- a/tests/test_deserialize.py
+++ b/tests/test_deserialize.py
@@ -16,11 +16,11 @@ def test_deserialize_int():
 
 
 def test_deserialize_fp():
-    serialized = '2780037 0'
+    serialized = '2780037 false'
     deserialized = deserializer(serialized, 'FP16x16')
     assert isclose(deserialized, 42.42, rel_tol=1e-7)
 
-    serialized = '2780037 1'
+    serialized = '2780037 true'
     deserialized = deserializer(serialized, 'FP16x16')
     assert isclose(deserialized, -42.42, rel_tol=1e-7)
 
@@ -36,7 +36,7 @@ def test_deserialize_array_int():
 
 
 def test_deserialize_arr_fixed_point():
-    serialized = '[2780037 0 2780037 1]'
+    serialized = '[2780037 false 2780037 true]'
     deserialized = deserializer(serialized, 'Span<FP16x16>')
     expected = np.array([42.42, -42.42], dtype=np.float64)
     assert np.all(np.isclose(deserialized, expected, atol=1e-7))
@@ -54,11 +54,16 @@ def test_deserialize_tensor_int():
 
 
 def test_deserialize_tensor_fixed_point():
-    serialized = '[2 2] [2780037 0 2780037 0 2780037 1 2780037 1]'
+    serialized = '[2 2] [2780037 false 2780037 false 2780037 true 2780037 true]'
     expected_array = np.array([[42.42, 42.42], [-42.42, -42.42]])
     deserialized = deserializer(serialized, 'Tensor<FP16x16>')
     assert np.allclose(deserialized, expected_array, atol=1e-7)
 
+def test_deserialize_matrix_fixed_point():
+    serialized = "{0: 2780037 false 2: 2780037 false 1: 2780037 true 3: 2780037 true} 4 2 2"
+    expected_array = np.array([[42.42, 42.42], [-42.42, -42.42]])
+    deserialized = deserializer(serialized, 'MutMatrix<FP16x16>')
+    assert np.allclose(deserialized, expected_array, atol=1e-7)
 
 def test_deserialize_tuple_int():
     serialized = '1 3'
@@ -75,14 +80,21 @@ def test_deserialize_tuple_span():
 
 
 def test_deserialize_tuple_span_tensor_fp():
-    serialized = '[1 2] [2 2] [2780037 0 2780037 0 2780037 1 2780037 1]'
+    serialized = '[1 2] [2 2] [2780037 false 2780037 false 2780037 true 2780037 true]'
     deserialized = deserializer(serialized, '(Span<u32>, Tensor<FP16x16>)')
     expected = (np.array([1, 2]), np.array([[42.42, 42.42], [-42.42, -42.42]]))
     npt.assert_array_equal(deserialized[0], expected[0])
     assert np.allclose(deserialized[1], expected[1], atol=1e-7)
 
-    serialized = '[2 2] [2780037 0 2780037 0 2780037 1 2780037 1] [1 2]'
+    serialized = '[2 2] [2780037 false 2780037 false 2780037 true 2780037 true] [1 2]'
     deserialized = deserializer(serialized, '(Tensor<FP16x16>, Span<u32>)')
     expected = (np.array([[42.42, 42.42], [-42.42, -42.42]]), np.array([1, 2]))
     assert np.allclose(deserialized[0], expected[0], atol=1e-7)
     npt.assert_array_equal(deserialized[1], expected[1])
+
+def test_deserialize_tuple_matrix_fp():
+    serialized = '[1 2]{0: 2780037 false 2: 2780037 false 1: 2780037 true 3: 2780037 true} 4 2 2'
+    deserialized = deserializer(serialized, '(Span<u32>, MutMatrix<FP16x16>)')
+    expected = (np.array([1, 2]), np.array([[42.42, 42.42], [-42.42, -42.42]]))
+    npt.assert_array_equal(deserialized[0], expected[0])
+    assert np.allclose(deserialized[1], expected[1], atol=1e-7)
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