Documentation of informed consent by patients entering clinical trials is an ethical and legal necessity. Federal regulations and judicial opinions have led to increasingly lengthy, detailed "consent" forms, yet published studies demonstrate that patients remain confused about the nature and anticipated consequences of study entry. It has been suggested that more detail may even alarm or further confuse patients. Seventy-five women undergoing chemotherapy for advanced breast cancer participated in this study which assessed patient preference for long-, medium-, or short-form length, and whether form length preference correlated with patient characteristics or indicators of patient autonomy in decision-making or physician dependency. Patient preferences for information were not predicted by the patient autonomy or physician dependency scores or by age, marital status, or level of education. The majority of patients expressed a preference for more detailed information about their treatment, yet a majority of patients given detailed forms answered questions basic to the study design incorrectly, irrespective of educational level. The increased detail included in the long forms was not reported to increase stress compared to the short forms. Patient information forms are a principal tool for informing patients for consent but if they are to perform their desired function they must be designed more carefully and evaluated more thoroughly than in the past.