Using data from a national survey of Ph.D.-holding chemists and physicists, time-to-doctoral degree is found to be a strong predictor of salary: each additional year in graduate school corresponds to a significantly lower average salary. This is true even while controlling for standard measures of scientific merit (grant funding and publication rates) and several other factors expected to influence salaries (field of research, type of position and rank, type of employing institution, years of seniority, and age). This picture is complicated by the inclusion of gender in the analysis, which reveals that women earn significantly less than men overall and experience no effect of doctoral completion time on their salaries, while men do see a significant gain in salary stemming from earlier completion times. Further investigation indicates that doctoral completion time is largely unconnected to measures of prior academic success, research independence, and scientific merit. This suggests that doctoral completion time is, to a great extent, out of the control of individual graduate students. Nonetheless, it can be influential on an individual's future career prospects, as can gender-related effects. (Contains 2 tables and 3 figures.)