<h3 class=""h3"">Summaryh3>A 17-year-old woman presented 1-week post caesarean section with septic arthritis which was unresponsive to first-line empirical antimicrobial therapy. Cultures of the hip aspirate revealed Mycoplasma hominis as the causative organism. M. hominis-associated septic arthritis is extremely rare in the absence of underlying joint abnormalities or immunosuppression. Strikingly four of the 26 cases reported have been pregnancy-associated.