There are few studies of strategic voting in PR elections. What types of strategic voting occur? How common is it for voters to cast their ballot for a party list other than that of their first preference? Does strategic voting affect legislative majorities and – eventually – government formation even if legislative seats are allocated by a proportional electoral formula in multi-member districts? We answer these questions based on data from the Norwegian general election in 2013. Our estimate indicates that a little less than ten percent of the voters voted strategically.