Aim: Current national guidelines state that it is mandatory to perform an estimation of renal function in all males with lower urinary tract symptoms (LUTS). As national audit evidence suggests this is not general practice, we have carried out a study to assess the value of routine testing of renal function in this group. Patients and Methods: Serum creatinine or urea was measured in 213 consecutive men presenting to the urology out-patient department with lower urinary tract symptoms. Risk factors for renal dysfunction such as large post-void residual volume, proteinuria, microscopic haematuria, diabetes mellitus and cardiovascular disease were noted. Results: Twelve of 213 patients had abnormal results. One 90-year-old had a raised serum urea but was found to have a normal creatinine level. Ten of the remaining 11 patients would have had their renal dysfunction predicted by history, examination or bedside tests. Conclusions: Routine measurement of creatinine or urea in men presenting with LUTS with no other risk factors could be considered purely a health screening test. It is suggested that it should no longer be considered as mandatory, in this situation, but used only if specifically indicated. A urine flow rate would be a more useful test in reaching a diagnosis and planning treatment.