An analysis is made of the contraceptive practice of 100 women prior to abortion. Half the women were not using any method during the month they became pregnant. Problems with the pill, risk-taking behaviour and fears of infertility, were the commonest reasons for non-use. In the 50 percent who were using a method, failure was most commonly due to human error and to the use of less reliable methods. Psychological and social factors were seen to be important determinants of behaviour. This study emphasises the need for remedial action.