Nongonococcal septic arthritis can occur during the postpartum period. We report two cases, one involving the wrist and the sacroiliac joints and the other the pubic symphysis. The difficulty of initial diagnosis in the postpartum period is emphasized. This pathology is uncommon and may begin insidiously. The sacroiliac joint is particularly at risk for postnatal sepsis, but its deep localization hinders investigations. Besides the classical obstetrical infectious assessment (blood cultures, urine culture, vaginal sample, white blood cell count and CRP) and radiological investigations, joint puncture is needed to isolate the causal infectious agent. Joint immobilization in combination with major 3-month antibiotic therapy is usually successful, generally with no sequellae.