A random sample of 34 families from the general population were studied over a 15-month period to determine their risk for depression over time. Adults and children in the families were interviewed three times during the 15-month period. Risk for depression was evaluated using four screening instruments, including the Diagnostic Interview Schedule. At the original interview, 40 percent of the families contained one or more members at risk for depression. The 15-month family incidence rate for risk for depression was 26 percent and of continued good mental health 74 percent. The mental health status of 35 percent of the families changed during the 15-month period, suggesting that longitudinal studies can provide a more accurate profile of family mental health than studies of families at a single point in time.