Previous research examining selection to legislative committees has assumed that the impact of constituency preferences on committee assignments is due to the incentives for individual legislators to use their committee seats to increase their personal chances of re-election. Examining the case of the Mexican Chamber of Deputies (where legislators were, until recently, barred from re-election), this study argues that the impact of constituency preferences on selection to committees also occurs because parties have incentives for their members to use committee assignments to increase the party’s chances of being re-elected. Analysis of assignments to 11 committees over 4 legislative terms provides support for the argument. These findings reinforce previous research arguing that concerns with constituency representation and its impact on re-election also apply to political parties and not solely to individual legislators.