Abnormalities of renal handling of urate occur in a wide variety of physiological and pathological conditions and are mediated by factors including renal blood flow, glomerular filtration rate, urine flow rate, urinary constituents, metabolites, hormones and drugs. The determination of the aetiological factors in each abnormal situation is complex and the problem is discussed in relation to a variety of conditions including renal tubular disorders and metal intoxications, hypertension, toxaemia of pregnancy, glycogen storage disease, fructose administration, hereditary fructose intolerance, as well as obesity, regular alcohol consumption and hyperlipoproteinaemia. Apart from those diseases, usually genetically determined, which are associated with excessive production of urate, the most common causes of hyperuricaemia act at a renal level and result in a reduction in the net renal excretion of urate.