Objective: Low socioeconomic status (SES) in childhood confers risk for poor physical health later in life. This study prospectively examines whether improvements in family SES protect youth from developing physical health problems by adulthood and whether such effects differ by race or age. Method: Participants are a school-based sample of urban Black (53%) and White (47%) men (N = 311). Using latent growth curve modeling, we prospectively examined whether changes in family SES measured annually between Ages 7 and 16 predicted physical health diagnoses in adulthood (Age 32). Family SES was assessed as a weighted composite of parental education and occupational status. Physical health diagnoses were assessed as a count of self-reported medical conditions from a health history interview. Results: Consistent with macroeconomic trends, on average, family SES increased until the early 1990s, then remained flat until rising again in the mid-1990s. During each of 3 independent developmental periods, boys raised in families who experienced more positive changes in SES reported fewer physical health diagnoses in adulthood. These effects did not vary significantly by race and remained after controlling for initial childhood SES, childhood health problems, concurrent adult SES, and weight (Body Mass Index or reported overweight). Conclusions: Initial childhood SES did not predict physical health, whereas relative improvements in SES over a 10-year period did. If the families of Black and White boys were upwardly mobile, it appeared to protect them from developing physical disease, and upward mobility was additively protective across developmental periods examined here.