With impending health care reform in the USA, there is an imperative to increase the number of students choosing primary care (PC) careers. Research is needed to better understand the roles of economic factors in medical student career choice. The objective of this study was to examine the relationships among debt, income and career choice by comparing students planning PC careers with those aspiring to one of the 12 non-PC fields in which median income exceeds US$300 000 ('high-paying non-primary care' [HPNPC]). Surveys (response rate = 81%) were administered to Year 1 students scheduled to graduate between 1996 and 2012, and Year 4 students graduating between 1993 and 2010. Respondents were students at New York Medical College and East Carolina University's Brody School of Medicine. Analyses focused on the 2674 Year 1 respondents choosing a PC (n = 1437, 54%) or HPNPC (n = 1237, 46%) career, and the 2307 Year 4 respondents intending to pursue PC (n = 992, 43%) or HPNPC (n = 1315, 57%). Longitudinal analyses examining changes in career goals during medical school were based on students who completed surveys in both Years 1 and 4. The outcome measures studied were self-reported debt, anticipated income and self-rated value placed on income. Relative to their PC counterparts, students intending to pursue HPNPC careers anticipated an average of US$24 904 (Year 4 students) or US$29 237 (Year 1 students) greater debt, placed a higher importance value on income, and anticipated earning an average of US$58 463 (Year 1 students) and US$89 909 (Year 4 students) more in annual income after graduation. Debt was associated with the value placed on income in the choice of career and the amount of future income anticipated. Students who valued income highly were especially inclined to switch from PC during medical school. The switch away from PC was associated with debt, as well as with a marked increase in anticipated income. Debt and anticipated income are important concerns which may shape future supplies of PC doctors. © Blackwell Publishing Ltd 2012.