Bench press 1-RM test is a common assessment to measure maximal strength of the upper body musculatures. Most protocols recommend a rest period between the maximum contraction trials to avoid fatigue which may confound the assessment. Factors that influence fatigue are strength level and fatigue recovery rate especially among sedentary population. The objective of this study was to determine the optimal resting period required among sedentary population when assessing upper body strength using the common 1-RM test, and whether gender influenced the findings. In a randomised, cross-over design, thirty (15 males and 15 females) sedentary participants, aged 18 to 24 years underwent 1-RM bench press tests using machine weight and free weight with different rest period between the 1-RM trials (1-min, 3-min, 5-min). The participants lifted a significantly (p < 0.05) heavier weight when given 3-min rest for both machine weight test (47.16 ± 26.86 kg) and free weight test (40.73 ± 22.03 kg), as well as when given 5-min rest for both machine weight test (48.11 ± 26.91 kg) and free weight test (42.00 ± 24.67 kg), compared to the 1-min rest group for both machine weight test (41.30 ± 24.31 kg) and free weight test (37.11 ± 22.06 kg), for both gender. There was no significant difference between 3-min and 5-min rest periods for both types of weights. There was also no significant difference between the rest periods needed for both gender in both types of weights. Three-min rest interval is enough for sedentary people irrespective of gender for 1-RM strength assessment on either machine weigh bench press or free weight.