OBJECTIVE: To review and analyze the regulatory framework of clinical trial registration, use of existing tools (publicly accessible national/international registration databases), and users' perspectives to identify possible barriers to registration compliance by sponsors and researchers in Argentina. METHODS: Internationally registered trials recruiting patients in Argentina were found through clincialtrials.gov and the International Clinical Trial Registration Platform (ICTRP) and compared with publically available clinical trials registered through the National Administration of Drugs, Foods, and Medical Devices (ANMAT). A questionnaire addressing hypothesized attitudinal, knowledge-related, idiomatic, technical, economic, and regulatory barriers that could discourage or impede registration of clinical trials was developed, and semi-structured, in-depth interviews were conducted with a purposively selected sample of researchers (investigators, sponsors, and monitors) in Argentina. RESULTS: A response rate of 74.3% (n = 29) was achieved, and 27 interviews were ultimately used for analysis. Results suggested that the high proportion of foreign-sponsored or multinational trials (64.8% of all protocols approved by ANMAT from 1994-2006) may contribute to a communication gap between locally based investigators and foreign-based administrative officials. A lack of knowledge about available international registration tools and limited awareness of the importance of registration were also identified as limiting factors for local investigators and sponsors. CONCLUSIONS: To increase compliance and promote clinical trial registration in Argentina, national health authorities, sponsors, and local investigators could take the following steps: implement a grassroots educational campaign to improve clinical trial regulation, support local investigator-sponsor-initiated clinical trials, and/or encourage local and regional scientific journal compliance with standards from the International Committee of Medical Journal Editors (ICMJE) and/or the World Association of Medical Editors (WAME)