An investigation was made as to whether studies have found journal clubs for physicians in training to be effective for improving patient care, teaching critical appraisal skills, improving reading habits, increasing knowledge of clinical epidemiology and biostatistics, and increasing the use of medical literature in clinical practice. A literature search was undertaken using 10 databases and retrieval systems and hand searches of journals, conference proceedings and personal files. The rigor of studies meeting the inclusion criteria was analyzed using a protocol based on methods established by the Cochrane Collaboration. One randomized controlled trial found an improvement in knowledge of clinical epidemiology and biostatistics, reading habits, and the use of medical literature in practice, but no improvement in critical appraisal skills. Six less methodologically rigorous studies found possible improvement in critical appraisal skills. It is concluded that journal clubs may improve knowledge of clinical epidemiology and biostatistics, reading habits, and the use of medical literature in practice. A multicenter, randomized controlled trial of journal clubs is needed to assess whether journal clubs improve critical appraisal skills.