The policymaking component of representation in the United States and Great Britain has been closely studied and compared, but the constituency component—the handling of constituent complaints and the protection of constituency interests—is less well understood. This article considers two questions about the constituency component of representation: how much and what kinds of casework services do MPs as opposed to members of Congress provide, and second, what are the statistical determinants of these activities? With regard to the first question, our findings indicate that MPs devote more of their own time to constituency work than do members of Congress. In addition, we identify representatives on both sides of the Atlantic who adopt a more aggressive strategy toward their constituency work. This strategy is manifested by such activities as publicizing successful cases, handling cases that concern local government matters, the frequency of surgeries, and the active solicitation of cases. In the second part of this article, we model these activities as being related to the electoral margin, party, and the year the representative was elected. These estimations indicate that casework entrepreneurs in both countries are most likely to be in marginal seats, recently elected, and Democrats or Labour.