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. To determine the subsequent academic success of recipients of National Institutes of Health (NIH) career development awards. United States. 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. 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. 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. 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. Only a minority of K awardees studied achieved R01 award funding during the period assessed, and a significant sex disparity was evident.