Strength assessment is often part of the objective periodical observation of teams, squads, or large groups of athletes. Equipment that provides assessment that is mobile and is easy to use will reduce the impact on the athletes' training and competitive calendar. However, any equipment used must be reliable to allow accurate monitoring of performance. The aim of this study was to examine the reliability of the Concept2 Dyno dynamometer. Forty-six competitive athletes (males: n = 36, age 23.3 ± 6.8 years, height 1.80 ± 0.09 m, body mass 82.3 ± 15.6 kg; females, n = 10, age 20.7 ± 1.4 years, height 1.65 ± 0.09 m, body mass 62.7 ± 11.8 kg), with a strength training background of more than 2 years, performed a familiarization session and 3 experimental sessions with 1 week intervening each. Each experimental session consisted of 3 maximal efforts of seated chest press (CPress), seated row (SRow), and seated leg press (LPress) exercises. Reliability was assessed examining systematic bias, intraclass correlation coefficient, coefficient of variation (CV), and 95% limits of agreement (95% LoA) between sessions. No systematic bias was found for any of the exercises. Intraclass correlation coefficients were high (0.89-0.98) with relatively low CV (6.2-4.3%). Finally, 95% LoA indicated that subsequent testing could underestimate by a factor of 0.87 or overestimate by a factor of 1.17, on average. These results indicate that Concept2 Dyno dynamometer is reliable and can be used in the field to efficiently monitor strength performance. Coaches and researchers should use "analytical goals" to help decide as to the use of Concept2 Dyno for their purposes.