Clinical experience suggests fluctuation in the occurrence of osteoarticular infections. We performed a single-centre study during 2004-2012, dividing each year into the four seasons according to the Gregorian calendar. A total of 455 episodes of osteoarticular infections were retrieved. There were 91 prosthetic joint infections (45 of haematogenous origin) and 159 cases of septic arthritis. The median period between early symptoms and diagnosis of infection was 27 days. The overall number of infections per season, cumulated over the 8-year study period, was 119 in spring, 129 in summer, 95 in fall, and 112 in winter, which did not reflect any significant seasonal fluctuation. None of the different subgroups of infections, namely arthroplasties (p for trend = 0.755), haematogenous arthroplasty infections (p = 0.493), gram-negative episodes or arthritis (p = 0.290), showed any season-related fluctuation. We conclude that osteoarticular infections, including haematogenous prosthetic joint infections, do not show any significant seasonality.