The incidence and prevalence rates of connective tissue disease syndromes in Rochester, Minnesota, from 1950 through 1979 are reported. The incidence of definite systemic lupus erythematosus (SLE) has not increased since 1960. The incidence of SLE in the elderly population was higher than that in previous reports. Rates of SLE and discoid lupus erythematosus were approximately equal. Other diagnoses (in decreasing order of frequency) were suspected lupus erythematosus, scleroderma, drug-induced lupus, and overlapping connective tissue disease syndromes. The 10-year survival of patients with definite SLE was decreased, and the survival of patients with suspected SLE was the same as that of the general population.