This study investigated the physiological, anthropometric, and skill characteristics of rugby league players and determined the relationship between physical fitness and playing ability in these athletes. Eighty-six rugby league players (mean +/- SD age, 22.5 +/- 4.9 years) underwent measurements of standard anthropometry (height, body mass, and sum of 4 skinfolds), muscular power (vertical jump), speed (10-, 20-, and 40-m sprint), agility (L run), and estimated maximal aerobic power (multistage fitness test). In addition, 2 expert coaches independently assessed the playing ability of players using standardized skill criteria. First-grade players had significantly greater (p < 0.05) basic passing and ball-carrying ability and superior skills under fatigue, tackling and defensive skills, and evasion skills (i.e., ability to beat a player and 2 verse 1 skills) than second-grade and third-grade players. While no significant (p > 0.05) differences were detected among playing levels for body mass; skinfold thickness; height; 10-, 20-, or 40-m speed; agility; vertical jump height; or estimated maximal aerobic power, all the physiological and anthropometric characteristics were significantly (p < 0.05) associated with at least 1 measure of playing ability. The results of this study demonstrate that selected skill characteristics but not physiological or anthropometric characteristics discriminate between successful and less successful rugby league players. However, all physiological and anthropometric characteristics were related to playing ability. These findings suggest that while physiological and anthropometric characteristics do not discriminate between successful and less successful rugby league players, a high level of physical fitness contributes to effective playing ability in these athletes. A game-specific training program that incorporates both physical conditioning and skills training may facilitate a greater transfer of physical fitness to competitive performances in rugby league.