diff --git a/src/kyupy/__init__.py b/src/kyupy/__init__.py
index cd42d1b..2ed27f8 100644
--- a/src/kyupy/__init__.py
+++ b/src/kyupy/__init__.py
@@ -29,7 +29,7 @@ def popcount(a):
 def readtext(file):
     """Reads and returns the text in a given file. Transparently decompresses \\*.gz files."""
     if hasattr(file, 'read'):
-        return file.read()
+        return file.read().decode()
     if str(file).endswith('.gz'):
         with gzip.open(file, 'rt') as f:
             return f.read()