One hundred and fifty-three patients with renal stones referred to one teaching hospital have received extracorporeal shock wave lithotripsy (ESWL) treatment as a result of a monthly sessional arrangement organised with a neighbouring lithotripter unit. The results of treatment, assessed 3 months after lithotripsy, showed results comparable with those from any lithotripter centre. Sessional access for lithotripsy may provide a satisfactory way of increasing the number of patients who are treated with lithotripsy by reducing the demand for beds at the hospitals where a lithotripter is sited.