Two experiments assessed the effects of mugshot commitment on the ability to make a subsequent lineup identification. Young (17–37 years) and older (55–87 years) participants viewed a crime video featuring a younger (20 years) or older (64 years) culprit. Some participants viewed a 50-photograph culprit-absent mugbook. Following a 1-week delay, participants returned to view a culprit present lineup. In Experiment 1, mugbook choosers tended to select their prior selection in the lineup and mugbook nonchoosers tended to reject the lineup. In Experiment 2, mugshot choosers rejected a lineup that did not contain their prior selection. Commitment to a prior selection and commitment to a selection strategy were the cause of the majority of lineup errors. As previously reported, mugshot exposure harms subsequent lineup identification, and this appears to be primarily the result of commitment effects. Copyright © 2008 John Wiley & Sons, Ltd.