This article analyzes the primary scholarship activities of agricultural college plant science faculty with and without Extension appointments using survey data from all 1862 land-grant institutions. The evidence suggests that differences between Extension professors and others without Extension appointments are small for minor Extension appointments, but show significant and increasing tradeoffs between Extension and research outputs above a 35-50% Extension appointment. The evidence is suggestive of the potential for gains from exploiting complementarities between Extension and research rather than from pursuing high levels of specialization. The work concludes with implications for the role of state specialists in Extension. (Contains 7 figures and 2 tables.)