A total of 11 patients with refractory pain secondary to autosomal dominant polycystic kidney disease underwent ultrasound guided percutaneous aspiration of cyst fluid on the affected side. Surgical reduction of cyst volume was performed if pain recurred. Dramatic relief of pain was observed after both procedures. The probability of a patient being free of renal pain at 18 months was 33 +/- 17 per cent for aspiration and 81 +/- 12 per cent for an operation. Individual patients had relief of pain for more than 4 years. There was no deleterious effect on renal function after either aspiration or an operation. Blood pressure improved in the 5 patients with hypertension. There were no complications of percutaneous cyst aspiration. One patient required neurolysis of the drain site after cyst reduction.