So far in Orphan Black Tatiana Maslany has played the following characters:

deardarkness:

• Sarah Manning
• Beth Childs
• Alison Hendrix
• Katja Obinger
• Cosima
• Helena
• Sarah pretending to be Beth
• Alison pretending to be Sarah
• Sarah pretending to be Katja
• Helena pretending to be Sarah who is pretending to be Beth

And there has only been four episodes so far. She is crazy talented in that Anna Torv plays a million Olivia Dunhams way.

I love this show