We studied the renal urate excretory function in two groups of hyperuricaemic male patients composed of individuals with associated hyperlipidemia and hyperuricaemic-normolipidemic individuals, respectively. Both the hyperlipidemia and the hyperuricaemia were primary inasmuch as none of the patients studied was obese or had an above-normal alcohol intake or blood hypertension. The results obtained show that hyperuricaemic-hyperlipidemic patients have higher serum levels of uric acid and poorer urate excretion as reflected in smaller clearance and fractioned excretion of the metabolite than hyperuricaemic-normolipidemic patients. This, in turn, suggests the occurrence of differences in the extent of the urate handling anomalies between the two groups of patients.