OBJECTIVE: To investigate shoulder pain incidence rates and selected risk factors for shoulder pain in competitive swimmers. DESIGN: 12-month prospective cohort study. SETTING: Five swimming clubs in Melbourne, Australia. PARTICIPANTS: 74 (37 M, 37 F) competitive swimmers ranging in age from 11 to 27 years and performing at least five swim sessions per week. ASSESSMENT OF RISK FACTORS: Swimmers completed a baseline questionnaire regarding demographics, anthropometric features, swimming characteristics and training and injury history. Active shoulder internal (IR) and external rotation (ER) range of motion and passive joint laxity were measured. MAIN OUTCOME MEASUREMENTS: Shoulder pain was self-reported over 12 months with significant interfering shoulder pain (SIP) defined as pain interfering (causing cessation or modification) with training or competition, or progression in training. A significant shoulder injury (SSI) was any SIP episode lasting for at least 2 weeks. RESULTS: 28/74 (38%) participants reported SIP while 17/74 (23%) reported SSI. Exposure-adjusted incidence rates were 0.3 injuries and 0.2 injuries per 1000 swim km for SIP and SSI, respectively. Swimmers with both high and low ER range were at 8.1 (1.5, 42.0) and 12.5 (2.5, 62.4) times greater risk of sustaining a subsequent SIP, respectively and 35.4 (2.8, 441.4) and 32.5 (2.7, 389.6) times greater risk of sustaining a SSI, respectively than those with mid-range ER. Similarly swimmers with a history of shoulder pain were 4.1 (95% CI: 1.3, 13.3) and 11.3 (95% CI: 2.6, 48. 4) times more likely to sustain a SIP and SSI, respectively. CONCLUSION: Shoulder pain is common in competitive swimmers. Preventative programs should be particularly directed at those swimmers identified as being at risk of shoulder pain.