Rugby union is a collision sport with a relatively high risk of injury. The ability of the Functional Movement Screen (FMS) or its component tests to predict the occurrence of severe (≥28 days) injuries in professional players was assessed. Ninety FMS test observations from 62 players across 4 different time periods were compared with severe injuries sustained during 6 months after FMS testing. Mean composite FMS scores were significantly lower in players who sustained severe injury (injured 13.2 ± 1.5 vs. noninjured 14.5 ± 1.4, Effect Size = 0.83, large) because of differences in in-line lunge (ILL) and active straight leg raise scores (ASLR). Receiver-operated characteristic curves and 2 × 2 contingency tables were used to determine that ASLR (cut-off 2/3) was the injury predictor with the greatest sensitivity (0.96, 95% confidence interval [CI] = 0.79–1.0). Adding the ILL in combination with ASLR (ILL + ASLR) improved the specificity of the injury prediction model (ASLR specificity = 0.29, 95% CI = 0.18–0.43 vs. ASLR + ILL specificity = 0.53, 95% CI = 0.39–0.66, p ≤ 0.05). Further analysis was performed to determine whether FMS tests could predict contact and noncontact injuries. The FMS composite score and various combinations of component tests (deep squat [DS] + ILL, ILL + ASLR, and DS + ILL + ASLR) were all significant predictors of contact injury. The FMS composite score also predicted noncontact injury, but no component test or combination thereof produced a similar result. These findings indicate that low scores on various FMS component tests are risk factors for injury in professional rugby players.