Reviews of 22 studies between 1949 and 1969 of women who received tubal ligations primarily for contraceptive reasons are presented, as well as six studies of male reaction to vasectomy, including one study of female reaction to vasectomy. Previously suggested contraindications are thoroughly summarized. Tubal ligation studies in terms of patient characteristics are analyzed. Results show a greater per cent of regret over sterilization in studies in which: 1) attrition was under 30 per cent; 2) women reported less than four children; and 3) therapeutic abortion was performed concomitantly with sterilization. The identification of a response bias in favor of more satisfied patients in high attrition studies than in low attrition studies led to the conclusion that the prevalence of regret over sterilization has been underestimated. Actual prevalence may be as high as 25 per cent, which presents a clinical and social problem requiring extensive research. Findings are discussed in terms of previous research and clinical applications.The paper concludes that low parity and concomitant abortion are tentative risk factors for sterilization, although unsatisfied maternal desire may be more important than low parityper se.Other contraindications may include psychopathology, high religiosity, marital instability, misconceptions about the operation or about alternative methods of birth control, inability to accept loss, and recent severe loss. Psychological consultation is suggested to evaluate patient personality, attitudes toward reproductive function and body image, and possible effects on sexual role or self-image.The research reviewed suffered from methodological problems of design and measurement. Future research should attempt to eliminate the inclusion of patients with concomitant abortions, psychopathology, hysterectomy, or who are over age 45. Objective psychological measurement and ratings of adjustment by spouse or physician should supplement patient report of regret as outcome criteria. Reliability and validity of such outcome measures should be determined. Samples should be large enough to provide ample statistical power. Pre- and postoperative measures of adjustment are desirable once the epidemiology of adverse reaction is clear. Control groups of patients using other methods of birth control should be included to provide rational bases for choosing among relevant clinical alternatives. In addition to improving methodology, future research should try to determine the true prevalence of adverse reaction to sterilization, should compare couples switching from one method of birth control to another, and should investigate the processes involved in deciding to seek sterilization and in adjusting to it afterwards.