© 2019 Sports Medicine Australia Objectives: To examine the association between subjective health complaints, sleep quantity and new injury within an endurance sport population. Design: Prospective cohort study. Methods: Ninety-five endurance sporting participants were recruited from running, triathlon, swimming, cycling and rowing disciplines. Over 52-week period participants submitted weekly data regarding subjective health complaints (SHCs) (cardiorespiratory, gastrointestinal and psychological/lifestyle), sleep quantity, training load and new injury episodes. Applying a 7- and 14-day lag period, a shared frailty model was used to explore new injury risk associations with total SHCs and sleep quantity. Results: 92.6% of 95 participants completed all 52 weeks of data submission and the remainder of the participants completed ¿30 weeks. Seven-day lag psychological/lifestyle SHCs were significantly associated with new injury risk (Hazard ratio (HR) = 1.32; CI 95% = 1.01¿1.72, p < 0.04). In contrast, cardiorespiratory (HR = 1.15; CI 95% = 0.99¿1.36, p = 0.07) and gastrointestinal (HR = 0.77; CI 95% = 0.56¿1.05, p = 0.09) SHCs were not significantly associated with new injury risk. New injury risk had a significant increased association with 14-day lag <7 h/day sleep quantity (HR = 1.51; CI 95% = 2.02¿1.13, p < 0.01) and a significant decreased association with >7 h/day sleep quantity (HR = 0.63, CI 95% = 0.45¿0.87, p < 0.01. A secondary regression analysis demonstrated no significant association with total SHCs and training load factors (Relative Risk (RR) = 0.08, CI 95% = 0.04¿0.21, p = 0.20). Conclusions: To minimise an increased risk of new injuries within an endurance sporting population, this study demonstrates that psychological/lifestyle subjective health complaints and sleep quantity should be considered. The study also highlights a lag period between low sleep quantity and its subsequent impact on new injury risk. No association was demonstrated between subjective health complaints, sleep quantity and training load factors.