The number of articles published in open access journals has increased dramatically in recent years. Simultaneously, the quality of publications in these journals has been called into question. Few studies have explored the retraction rate from OAJs. The purpose of the current study was to determine the reasons for retractions of articles from OAJs in biomedical research. The Medline database was searched through PubMed to identify retracted publications in OAJs. The journals were identified by the Directory of Open Access Journals. (...) Data were extracted from each retracted article, including the time from publication to retraction, causes, journal impact factor, and country of origin. Trends in the characteristics related to retraction were determined. Data from 621 retracted studies were included in the analysis. The number and rate of retractions have increased since 2010. The most common reasons for retraction are errors, plagiarism, duplicate publication, fraud/suspected fraud and invalid peer review. The number of retracted articles from OAJs has been steadily increasing. Misconduct was the primary reason for retraction. The majority of retracted articles were from journals with low impact factors and authored by researchers from China, India, Iran, and the USA. (shrink)