BACKGROUND: Concerns have been raised about the career pipeline in academic medicine, including whether women with a demonstrated commitment to research succeed at the same rate as male colleagues. OBJECTIVE: To determine the subsequent academic success of recipients of National Institutes of Health (NIH) career development awards. SETTING: United States. PARTICIPANTS: 2784 of 2799 (99.5%) recipients of K08 and K23 awards for whom sex could be ascertained from the NIH Computer Retrieval of Information on Scientific Projects database and other publicly available sources. MEASUREMENTS: Actuarial rates at which recipients of K08 and K23 awards from 1997 to 2003 went on to receive R01 awards. Sex-specific rates of R01 award attainment were calculated by using the Kaplan-Meier method, and sex differences were assessed by using a Cox proportional hazards model. RESULTS: Overall, 31.4% of the 1919 K08 awardees and 43.7% of the 865 K23 awardees were female (P < 0.001). Women were less likely than men to receive an R01 award (P < 0.001). The actuarial rate of R01 award attainment at 5 years was 22.7% overall, 18.8% among women, and 24.8% among men. At 10 years, the rate was 42.5% overall, 36.2% among women, and 45.6% among men. Sex persisted as an independent significant predictor of R01 award attainment (hazard ratio, 0.79 [95% CI, 0.68 to 0.92]; P = 0.002) in multivariate analysis controlling for K award type, year of award, funding institute, institution, and specialty. LIMITATION: Whether the lower rate of R01 award achievement among women is due to lower rates of application or lower rates of success in application could not be determined. CONCLUSION: Only a minority of K awardees studied achieved R01 award funding during the period assessed, and a significant sex disparity was evident.