This paper investigates the occurrence of potentially avoidable perinatal deaths by associating failures in obstetric care with structural deficiencies in four maternity hospital comprising the local health care system in a city in Greater Metropolitan Rio de Janeiro in 1994. Information sources were a questionnaire, interview, observation, and hospital records. A theoretical organizational model was applied in data analysis. The four maternity hospitals showed problems in the three groups of factors used in this study: physical infrastructure, services, and equipment; organizational and administrative characteristics; and professional organization. In two maternity hospitals, the delay in cesarean deliveries was explained by deficiencies in the group of factors that includes facilities, services, and equipment. Health care failures directly associated with the physician were explained by high percentages of negative predisposing factors (mainly in the two private hospital), skill-related problems (more clearly in the two public hospitals), and by absence of measures for redirecting practice.