diff --git a/soaplib/soap.py b/soaplib/soap.py
index f6a59cc..082e85f 100644
--- a/soaplib/soap.py
+++ b/soaplib/soap.py
@@ -126,7 +126,7 @@ def from_soap(xml_string):
     '''
     Parses the xml string into the header and payload
     '''
-    root, xmlids = ElementTree.XMLID(xml_string)
+    root, xmlids = ElementTree.XMLID(xml_string.encode()) 
     if xmlids:
         resolve_hrefs(root, xmlids)
     body = None