BACKGROUND: The one-repetition maximum (1RM) test is the most widely used method to analyze muscular strength. However, the 1RM reliability may be dependent on previous resistance training experience. OBJECTIVE: The purpose of the study was to analyze the reliability of 1RM test in detrained men with previous resistance training experience. METHODS: Sixty-seven men (21.1 years, 71.4 kg, 174.1 cm, 23.5 m/kg 2 ) were recruited and allocated to one of the three groups, according to their previous experience in resistance training: Novice (n = 29, from 1 to 6 months), Intermediate (n = 19, from 7 to 12 months), and Advanced (n = 19, from 13 to 24 months). All subjects performed the 1RM test in the bench press, squat, and arm curl in four sessions. At each session the subjects performed three attempts to reach a peak strength level for each exercise. RESULTS: Significant increases (P < 0.05) in maximal strength between the first and fourth sessions were consistent for each group in bench press (8.3% to 9.8%), squat (14.9% to 18.5%), and arm curl (7.6% to 10.0%) with no group-by-time interaction. CONCLUSION: Despite two years of previous RT experience men need at least two 1RM sessions to achieve accurate maximal strength baseline scores, Thus, a minimum two-trial 1RM assessment may be the standard for determining a maximal strength baseline in order not to underestimate achievement.