Six thousand ninety-two men who had undergone vasectomy were observed for 20,491 person-years of observation in a prepaid group practice. The incidences of first-time hospitalizations for a variety of diagnoses were examined as a proxy for disease incidence rates and compared with similarly derived rates in the remaining male membership of the practice. Vasectomized men had comparatively high rates of hospitalization for a variety of diseases of the genitourinary system during the early postvasectomy period. Apart from these, there were no important, statistically convincing elevations in the new hospitalization rates among vasectomized men, as compared with those of the nonvasectomized comparison group.
