Hi > Short answer: Reverse the string first. I'm new to this python stuff and to this newsgroup too.. but why you don't use 'rfind' instead of 'find'? I think that's much easier... somthing like: import string str = 'ac ab ab ac' res = string.rfind(str, 'ac', 0, len(str)) print 'last position :', res SEE yA PS sorry for bad english and grammar