Urinary tract stones and urinary tract infection are strongly associated. Infection is implicated as the cause of stones in about 15% of stone formers, and the development of infection can complicate the management of pre-existing stones. Left untreated, both situations can result in loss of kidney function, and can, on occasion, be life threatening. The underlying pathophysiology of infection stones is generally well understood, but factors dictating why a particular individual should be affected are less clear, although obstruction is a uniformly recognized risk factor. Surgery is the mainstay of treatment for infection calculi: stone clearance is the goal and a range of minimally invasive treatments is available. Systemic sepsis remains the most serious complication of treatment, and, although rare, still occurs despite antibiotic prophylaxis. Once the stone and the causative infection have been removed, various strategies can be employed to minimize the risk of recurrence. When infection complicates pre-existing stone disease, the primary aim of management is to treat the infective episode and delay definitive stone management until the infection has cleared. In such cases where obstruction is also present, prompt drainage of the affected kidney is likely to prevent permanent renal damage, and may be life saving.