OBJECTIVES: To assess reporting quality of studies using routinely collected health data (RCD) to inform the REporting of studies Conducted using Observational Routinely collected health Data (RECORD) guideline development. STUDY DESIGN AND SETTING: PubMed search for observational studies using RCD on any epidemiologic or clinical topic. Sample of studies published in 2012. Evaluation of five items based on the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guideline and eight newly developed items for RCD studies. RESULTS: Of 124 included studies, 39 (31.5%) clearly described its design in title or abstract. Complete information to frame a focused research question, that is, on the population, intervention/exposure, and outcome, was provided for 51 studies (41.1%). In 44 studies where definitions of codes or classification algorithms would be necessary to operationalize such a research question, only nine (20.5%) reported all items adequately. In 81 studies describing multivariable analyses, 54 (66.7%) reported all variables used for modeling and 34 (42.0%) reported basic details required for replication. Database linkage was reported adequately in 12 of 41 studies (29.3%). Statements about data sharing/availability were rare (5/124; 4%). CONCLUSION: Most RCD studies are insufficiently reported. Specific reporting guidelines and more awareness and education on their use are urgently needed.