Abstract Creatine is consumed by athletes to increase strength and gain muscle. The aim of this study was to evaluate the effects of creatine supplementation on maximal strength and strength endurance. Twelve strength-trained men (25.2 ± 3.4 years) supplemented with 20 g Creatina + 10g maltodextrin or placebo (20g starch + 10g maltodextrin) for five days in randomized order. Maximal strength and strength endurance (4 sets 70% 1RM until concentric failure) were determined in the bench press. In addition, blood lactate, rate of perceived effort, fatigue index, and mood state were evaluated. All measurements were performed before and after the supplementation period. There were no significant changing in maximal strength, blood lactate, RPE, fatigue index, and mood state in either treatment. However, the creatine group performed more repetitions after the supplementation (Cr: Δ = +3.4 reps, p = 0.036, g = 0.53; PLA: Δ = +0.3reps, p = 0.414, g = 0.06), and higher total work (Cr: Δ = +199.5au, p = 0.038, g = 0.52; PLA: Δ = +26.7au, p = 0.402, g = 0.07). Creatine loading for five days allowed the subjects to perform more repetitions, resulting in greater total work, but failed to change the maximum strength. muscle strengthtrained trained 25.2 252 25 2 (25. 34 3 4 3. years 20g order ( 70 RM failure press addition lactate effort index evaluated period RPE treatment However Cr (Cr +3. reps 0036 0 036 0.036 0.53 053 53 PLA 03reps 3reps +0.3reps 0414 414 0.414 0.06, 006 0.06 , 06 0.06) 1995au au 199 5au +199.5au 0038 038 0.038 0.52 052 52 267au 26 7au +26.7au 0402 402 0.402 0.07. 007 0.07 . 07 0.07) 25. (25 7 +3 003 03 0.03 0.5 05 5 041 41 0.41 00 0.0 19 040 40 0.40 (2 0. 04 0.4 1