Objective: To determine the clinical utility of screening for biochemical parameters in elite athletes. Design: A prospective sequential case series Setting: The Department of Sports Medicine at the Australian Institute of Sport Participants: One hundred elite athletes from eleven sports, 56 males and 44 females, mean age for both groups 19 years, undergoing routine medical screening. Intervention: Initial and follow-up assessment of the following biochemical parameters in association with clinical assessment; serum iron, ferritin, transferrin, percent transferrin saturation, sodium, potassium, chloride, calcium, magnesium, phosphate, urate, urea and creatinine, total protein, albumin, creatine kinase (CK), lactate dehydrogenase (LDH) , aspartate aminotransaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), total bilirubin, cholesterol and triglycerides (non-fasting) and random glucose (BSL). Results: Eighteen athletes demonstrated no abnormalities on biochemical screening. One hundred and ninety-four abnormal results were found in 82 athletes. One hundred and fifteen abnormalities were noted in 46 males and 79 in 36 females. In forty three individual tests the results did not return to normal on repeat testing. The most frequently demonstrated abnormalities were increased AST (27%), increased phosphate (13%), increased CK (13%), increased urea (12%) and increased bilirubin (12%). Three cases of hypercholesterolaemia and one case of haemochromatosis were identified and one athlete, who was symptomatic, was diagnosed with Epstein-Barr virus infection suspected when abnormal liver function test were noted. The other abnormalities found appeared not to be of clinical significance. Conclusion: The vast majority of abnormalities found on routine biochemical screening in elite athletes are of no clinical significance. Therefore such testing should, if used only for clinical purposes, be abandoned. When athletes are tested for iron status it would be prudent to include assessment of serum cholesterol in those with a family history of hyperlipidaemia.