Improving condom acceptability amongst users is one way to enhance efficacy. This study aimed to test whether or not the shape of a condom influenced users’ perceptions of condom acceptability as measured through their ratings of condom comfort, sensitivity and security. Four types of condoms were tested which had 3 different shapes, and one of which also had a small diameter. Participants were recruited at 15 UK Family Planning Research Network Clinics and one Student Health Centre in England and Wales in late 1997. A total of 1193 people initially volunteered to take part and of these 204 men and 251 women completed the trial, giving an overall response rate of 38%. Results suggest that both men and women were able to detect differences in the shapes of the condoms and that differences led to preference for a particular condom type. Similar proportions preferred a straight-sided, a flared and a contoured condom, whilst the smaller, contoured condom was preferred by a minority of respondents. To optimize consistent condom use, providers should consider encouraging users to try a range of condoms to ensure that they are using the one most suitable for them.