Probably every major text on epidemiology offers at least some discussion of recall bias in retrospective research. A potential for recall bias exists whenever historical self-report information is elicited from respondents. Thus-, the potential for its occurrence is greatest in case-control studies or cross-sectional studies which include retrospective components. Recall bias is said to occur when accuracy of recall regarding prior exposures is different for cases versus controls. The current paper will describe the process and consequences of recall bias. Most critically, it will suggest methods for assessment and adjustment of its effects.