BACKGROUND AND OBJECTIVE. Clinical epidemiology and statistics skills of clinical researchers are often limited. We assessed methodological skills of medical researchers and identified factors associated with higher skill levels. METHODS. In a cross-sectional mail survey at two Swiss teaching hospitals, participants (N = 409) rated their ability to perform 26 research-related activities, such as identifying the research question, selecting a study design, computing the required sample size, performing data analysis, and reporting results. RESULTS. The proportion of respondents who were able to perform a specific activity was 33.2% on average, ranging from 1.5% for "numerical statistics (bootstrap, simulation, cross-validation,...)" to 76.0% for "oral presentation of results." The overall skill level (expressed as a percentage of the 26 activities) was associated with principal investigator experience (+8.7%), greater percentage of time devoted to research (+12.4% for near full-time versus no time commitment), years of research experience (+17.6% for 15-40 years versus 0 years), past number of clinical research projects (+18.0% for 15-230 projects versus 0-1 projects), and hours of formal methodological training (+32.6% for 200-1200 hours versus 0-9 hours). CONCLUSION. Self-reported methodological skills were generally modest. The most important covariates of skill levels were current time commitment to research, past experience, and formal training. [Authors]