Geminin was originally identified as an inhibitor of replication initiation, but is now known to play multiple roles in several fundamental cellular processes including proliferation, differentiation, development and transcriptional regulation. Recently, the functional properties of geminin have been further characterized by identifying geminin binding partners. To gain a broader molecular view of geminin's role in the control of cellular functions, we performed yeast two-hybrid screening. In this review, we will describe several novel binding partners of geminin, particularly those involved in the DNA repair process performed by TopBP1, as well as some unexpected roles of geminin in various cellular events.