diff --git a/patoolib/programs/py_bz2.py b/patoolib/programs/py_bz2.py
index 2be3669..71be192 100644
--- a/patoolib/programs/py_bz2.py
+++ b/patoolib/programs/py_bz2.py
@@ -54,7 +54,7 @@ def create_bzip2 (archive, compression, cmd, *args, **kwargs):
     bz2file = bz2.BZ2File(archive, 'wb')
     try:
         filename = args[0]
-        with open(filename) as srcfile:
+        with open(filename, 'rb') as srcfile:
             data = srcfile.read(READ_SIZE_BYTES)
             while data:
                 bz2file.write(data)
diff --git a/patoolib/programs/py_gzip.py b/patoolib/programs/py_gzip.py
index 12c040e..7e7a4c4 100644
--- a/patoolib/programs/py_gzip.py
+++ b/patoolib/programs/py_gzip.py
@@ -52,7 +52,7 @@ def create_gzip (archive, compression, cmd, *args, **kwargs):
     gzipfile = gzip.GzipFile(archive, 'wb')
     try:
         filename = args[0]
-        with open(filename) as srcfile:
+        with open(filename, 'rb') as srcfile:
             data = srcfile.read(READ_SIZE_BYTES)
             while data:
                 gzipfile.write(data)
diff --git a/patoolib/programs/py_lzma.py b/patoolib/programs/py_lzma.py
index d02a146..c80e1c3 100644
--- a/patoolib/programs/py_lzma.py
+++ b/patoolib/programs/py_lzma.py
@@ -58,7 +58,7 @@ def _create(archive, compression, cmd, format, *args, **kwargs):
     lzmafile = lzma.LZMAFile(archive, 'wb', format)
     try:
         filename = args[0]
-        with open(filename) as srcfile:
+        with open(filename, 'rb') as srcfile:
             data = srcfile.read(READ_SIZE_BYTES)
             while data:
                 lzmafile.write(data)