Historically, few randomized controlled trials (RCTs) have been conducted in primary care and problems have been experienced applying this methodology in these settings. In 2001, The Leeds Evaluation of Efficacy of Detoxification Study (LEEDS) was developed. This RCT aimed to compare two detoxification drugs to inform best practice for the treatment of opiate users presenting to primary care requesting detoxification. This paper presents descriptive data from a postal survey of 12 general practitioners (GPs) from 10 primary care practices who were involved in the LEEDS trial. The questionnaire was sent out in November 2004, used open and closed questions and was self-administered. It uncovered factors that affected patient recruitment, GPs' views on the trial and their experience of randomizing opiate using patients. Flexible solutions to overcoming recruitment difficulties are presented alongside idealistic solutions to the problems experienced. The implications of our experiences of conducting this RCT in primary care practices are discussed in the light of conducting RCTs in primary care settings. This will benefit other research teams and clinicians who may be planning to use a similar research methodology.