diff --git a/CHANGELOG.md b/CHANGELOG.md
index 947d575c..0e467701 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## 1.2 -
 
+*   bugfix for python3+ where binary data was passed into a process's stdin [#325](https://github.com/amoffat/sh/issues/325)
 *   Introduced execution contexts which allow baking of common special keyword arguments into all commands [#269](https://github.com/amoffat/sh/issues/269)
 *   `Command` and `which` now can take an optional `paths` parameter which specifies the search paths [#226](https://github.com/amoffat/sh/issues/226)
 *   `_preexec_fn` option for executing a function after the child process forks but before it execs [#260](https://github.com/amoffat/sh/issues/260)
diff --git a/sh.py b/sh.py
index d3bb81a0..59fd1de5 100644
--- a/sh.py
+++ b/sh.py
@@ -1725,6 +1725,10 @@ def determine_how_to_read_input(input_obj):
         log_msg = "string"
         get_chunk = get_iter_string_reader(input_obj)
 
+    elif isinstance(input_obj, bytes):
+        log_msg = "bytes"
+        get_chunk = get_iter_string_reader(input_obj)
+
     else:
         log_msg = "general iterable"
         get_chunk = get_iter_chunk_reader(iter(input_obj))
diff --git a/test.py b/test.py
index 19a40161..2b4c9ace 100644
--- a/test.py
+++ b/test.py
@@ -640,6 +640,16 @@ def test_with_context_args(self):
         self.assertTrue(out == "")
 
 
+    def test_binary_input(self):
+        py = create_tmp_test("""
+import sys
+data = sys.stdin.read()
+sys.stdout.write(data)
+""")
+        data = b'1234'
+        out = python(py.name, _in=data)
+        self.assertEqual(out, "1234")
+
 
     def test_err_to_out(self):
         py = create_tmp_test("""
@@ -652,7 +662,7 @@ def test_err_to_out(self):
 sys.stderr.flush()
 """)
         stdout = python(py.name, _err_to_out=True)
-        self.assertTrue(stdout == "stdoutstderr")
+        self.assertEqual(stdout, "stdoutstderr")
 
 
     def test_err_piped(self):