Prosthetic joint infection (PJI) of the hip joint is a devastating complication after total hip arthroplasty (THA). Although rare, treatment of PJI is plagued with barriers to successful eradication of infection. Biofilm formation on implants causes treatment failure with quiescent bacteria avoiding debridement and antibiotics. Treatment nearly always requires surgery in the form of head-and-liner exchange, single-stage versus two-stage explantation-re-implantation, or a Girdlestone resection arthroplasty. This chapter outlines etiology, pathophysiology, prevention, and treatment of PJI of the hip.