diff --git a/NEWS.rst b/NEWS.rst
index 53b5667a..da42f57c 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -59,6 +59,11 @@ Bug Fixes
 
 * ``zstd_cffi.py`` added to ``setup.py`` (#60).
 
+Changes
+-------
+
+* Change some integer casts to avoid ``ssize_t`` (#61).
+
 0.10.1 (released 2018-10-08)
 ============================
 
diff --git a/c-ext/compressionwriter.c b/c-ext/compressionwriter.c
index 7a5be1be..cab6f52a 100644
--- a/c-ext/compressionwriter.c
+++ b/c-ext/compressionwriter.c
@@ -153,7 +153,7 @@ static PyObject* ZstdCompressionWriter_write(ZstdCompressionWriter* self, PyObje
 	input.size = source.len;
 	input.pos = 0;
 
-	while ((ssize_t)input.pos < source.len) {
+	while (input.pos < (size_t)source.len) {
 		Py_BEGIN_ALLOW_THREADS
 		zresult = ZSTD_compress_generic(self->compressor->cctx, &output, &input, ZSTD_e_continue);
 		Py_END_ALLOW_THREADS
diff --git a/c-ext/compressobj.c b/c-ext/compressobj.c
index 3ce0db9d..30399458 100644
--- a/c-ext/compressobj.c
+++ b/c-ext/compressobj.c
@@ -59,7 +59,7 @@ static PyObject* ZstdCompressionObj_compress(ZstdCompressionObj* self, PyObject*
 	input.size = source.len;
 	input.pos = 0;
 
-	while ((ssize_t)input.pos < source.len) {
+	while (input.pos < (size_t)source.len) {
 		Py_BEGIN_ALLOW_THREADS
 			zresult = ZSTD_compress_generic(self->compressor->cctx, &self->output,
 				&input, ZSTD_e_continue);
diff --git a/c-ext/decompressionwriter.c b/c-ext/decompressionwriter.c
index ee888791..e9084a1b 100644
--- a/c-ext/decompressionwriter.c
+++ b/c-ext/decompressionwriter.c
@@ -93,7 +93,7 @@ static PyObject* ZstdDecompressionWriter_write(ZstdDecompressionWriter* self, Py
 	input.size = source.len;
 	input.pos = 0;
 
-	while ((ssize_t)input.pos < source.len) {
+	while (input.pos < (size_t)source.len) {
 		Py_BEGIN_ALLOW_THREADS
 		zresult = ZSTD_decompress_generic(self->decompressor->dctx, &output, &input);
 		Py_END_ALLOW_THREADS