This study investigated the acceptability of rapid HIV testing among general practitioners (GP) and aimed to identify perceived barriers and needs in order to implement rapid testing in primary care settings. An anonymous questionnaire was distributed online to all members of the two largest Spanish scientific medical societies for family and community medicine. The study took place between 15 June 2012 and 31 October 2010. Completed questionnaires were returned by 1308 participants. The majority (90.8%) of respondents were GP. Among all respondents, 70.4% were aware of the existence of rapid tests for the diagnosis of HIV but they did not know how to use them. Nearly 80% of participants would be willing to offer rapid HIV testing in their practices and 74.7% would be confident of the result obtained by these tests. The barriers most commonly identified by respondents were a lack of time and a need for training, both in the use of rapid tests (44.3% and 56.4%, respectively) and required pre- and post-test counselling (59.2% and 34.5%, respectively). This study reveals a high level of acceptance and willingness on the part of GPs to offer rapid HIV testing in their practices. Nevertheless, the implementation of rapid HIV testing in primary care will not be possible without moving from comprehensive pre-test counselling towards brief pre-test information and improving training in the use of rapid tests.