BACKGROUND: Biomedical research is essential for optimizing patient care. Research has suggested inadequacies in nonorthopaedic trainees' understanding of study design and biostatistics. This study assesses orthopaedic residents' knowledge of common biostatistical and study design concepts, as well as their confidence in utilizing the medical literature. METHODS: A validated survey assessing knowledge and the application of study design concepts was administered to residents at 10 U.S. institutions. The survey tested knowledge as well as confidence and attitudes regarding common biostatistics principles. The association of demographic characteristics, work activities, and confidence and attitude ratings with test performance were examined using t tests and analysis of variance. RESULTS: The survey response rate was 64% (178 of 279). The largest group of participants were men (83%, 137 of 165), were between the ages of 26 and 30 years (59%, 105 of 177), and had graduated medical school within the past 4 to 10 years (43%, 76 of 175). Fifty-three percent (93 of 176) had prior biostatistics training, while 44% (77 of 176) had prior epidemiology training. Less than 5% of biostatistics or epidemiology training had taken place after medical school. Forty-seven percent (83 of 176) were unable to determine a study's design. Thirty-eight percent (67 of 178) could not apply the concept of specificity and sensitivity. Eighty-three percent (147 of 178) could not assess the strength of a relationship using odds ratios. Sixty-nine percent (123 of 178) understood the implications of p values. Previous biostatistics training, but not epidemiology or evidence-based medicine training; inclusion of reading research, attending conferences, and data analysis; as well as a self-reported finding of statistics as important for the analysis of one's own research data were significantly associated with better test performance (p < 0.05). CONCLUSIONS: Notable deficits exist in orthopaedic residents' biostatistical knowledge. Greater emphasis is needed to improve biostatistics and research design training. The impact of biostatistics knowledge and/or aptitude on clinical decision-making is an area of suggested research.