We studied which physiological and kinanthropometric characteristics determine climbing performance in 16 high-level sports climbers aged 29.9 +/- 4.9 years. Body composition parameters were measured with dual energy X-ray absorptiometry scanner. We also measured kinanthropometric and physical fitness parameters. The sex-specific 75th percentile value of onsight climbing ability was used to divide the sample into expert (<75th) and elite (>= 75th) climbers. All the analyses were adjusted by sex. The 75th percentile value of onsight climbing ability was 7b in women and 8b in men. There were no differences between expert and elite climbers in the studied variables, except in climbing time to exhaustion and bone mineral density. Elite climbers had a significantly higher time to exhaustion than the expert group (770.2 +/- 385 vs. 407.7 +/- 150 s, respectively, P = 0.001). These results suggest that, among climbers with a high level of performance, as those analysed in this study, climbing time to exhaustion is a major determinant of climbing performance.