This DataWatch examines the potential impact of socioeconomic differences on rates of hospitalization, based on patterns of hospital use in New York City in 1988. The research suggests that lack of timely and effective outpatient care may lead to higher hospitalization rates in low-income areas. For certain conditions identified as ambulatory care sensitive, hospitalization rates were higher in low-income areas than they were in higher-income areas where appropriate outpatient care was more readily available. Further study is needed to determine the relative impact of various economic, structural, and cultural factors that affect access to care.