OBJECTIVES: Trial registration can increase scientific transparency, but its implementation in specialty fields such as urology is unclear. We aimed to assess the endorsement of trial registration in the author instructions of urology-related journals and to assess whether randomized controlled trials (RCTs) in the field were effectively registered. DESIGN: Cross-sectional study of published trials. SETTING: We first assessed the author instructions of urology-related journals indexed in ‘Journal Citation Reports 2009’ (12/2010). Second, we divided the results into two groups of five journals each, all with high impact factors either requiring or not mentioning trial registration as a precondition for publication. We then performed a MEDLINE search to identify RCTs published in these 10 journals in 2009 (01/2011) and searched the clinical trials meta-search interface of the World Health Organization (ICTRP) for RCTs without information about registration (01–03/2011). Two authors independently assessed information regarding editorial advice about trial registration and identified the RCTs. RESULTS: Of 55 journals included, 26 (47.3%) contained some editorial advice about trial registration. Journals with high impact factors were more likely to mention trial registration directly (p=0.015). Of 106 RCTs published in 2009, 63 were registered (59.4%) with a tendency to an increase after 2005 (83.3%, p=0.035). 71.4% (30/42) of the RCTs that were published in journals mentioning and requiring registration, and 51.6% (33/64) of the RCTs that were published in journals that did not mention trial registration directly were registered. This difference was statistically significant (p=0.04). CONCLUSION: A statement of trial registration in author instructions resulted in a higher proportion of registered RCTs. Journals with high impact factors were more likely to mention trial registration. We suggest, though, that ensuring trial registration is not the responsibility only of the editors. Medical scientists should realize that trial registration is necessary to contribute to transparency in research.