The purpose of the present research is studying the effects of warm-up with two different sizes of balls on passing skills. Loughborough Soccer Passing Test (LSPT) was conducted on 28 non-elite football players, who participated in the present research for 10 training days. LSPT is a passing skill protocol established on completing 16 passes successfully in the shortest period of time possible (Ali et al., 2007). After 5 days implementation of LSPT, the participants were divided into 2 equal groups of 14, as experiment and control groups. During the second 5-day test period, control group participants warmed up with ball number 5, than took LSPT with the same ball. On the other hand, experiment group warmed up with ball number 4, and took LSPT with ball number 5. Obtained data were analysed with independent samples t-test, and accordingly experiment group was more successful than control group in LSPT (p< 0.01). Consequently, passing skills of football players who warmed up with ball number 4 were affected positively. The present research, which aimed at increasing match performance, predicted that passing skills were affected positively during the match among football players who warmed up with smaller size balls before the match.