Despite dramatic increases in use of hospital emergency rooms (ERs) since the 1950s, an estimated 85% of ER visits are made for non-life-threatening reasons. Using a modified version of the Andersen and Newman model of health care utilization, this paper reviews the research literature on ER use to examine what is known about factors that influence three stages of the help-seeking process: (1) problem recognition; (2) the decision to seek help; (3) the decision to use the ER. While predisposing factors other than race are not generally significant, enabling factors such as income, insurance coverage, having a usual source of care, and geographic proximity affect use of the ER, both alone and in interaction with race and other factors. The most common reason for non-urgent ER use was 'other care not available'. In addition to the absence of primary care, non-urgent use of the ER is linked to need factors arising from socioeconomic stress, psychiatric co-morbidities, and a lack of social support. Recommendations for future studies include examining prospectively all 3 stages of decision-making leading to ER use, and considering interactive effects among predictors. Implications for service delivery are discussed, including the need to re-structure health care delivery systems to provide greater access to primary care and provide more attention to psychosocial aspects of patient care in clinical settings.