It is still unclear whether the risk of hypertension and diabetes mellitus in adulthood remains increased if excess weight in adolescence recedes later in life. This study examines the effect of change in weight status from adolescence to young adulthood on the risk of hypertension and diabetes mellitus. A total of 4454 adolescents aged 12 to 19 years from the US National Longitudinal Study of Adolescent Health (1994-1995) were followed up to young adulthood (25-32 years, 2007-2008). After a median follow-up time of 13 years, compared with normal weight in both adolescence and young adulthood (n=1328, 29.8%), excess weight in the 2 periods (n=1077, 24.2%) was associated with an increased risk of hypertension (odds ratio, 3.72 [95% CI, 2.86-4.84]) and diabetes mellitus (3.32 [2.11-5.21]). Normal weight in adolescence but excess weight in young adulthood (n=1983, 44.5%) was associated with a lower but still significant risk of hypertension (2.49 [1.98-3.15]) and diabetes mellitus (1.59 [1.01-2.51]). In contrast, the risk of hypertension (1.37 [0.64-2.95]) and diabetes mellitus (1.65 [0.45-6.05]) was low in the few participants with excess weight in adolescence but normal weight in young adulthood (n=66, 1.5%). In conclusion, excess weight in young adulthood was associated with an increased risk of hypertension and diabetes mellitus, irrespective of weight status in adolescence. In contrast, excess weight in adolescence but normal weight in young adulthood did not seem to be associated with an increased cardiovascular risk in young adulthood.