The purpose of this study was to investigate the effects of ribose supplementation on swimming performance in collegiate male swimmers. Twenty trained collegiate male swimmers (mean ± SE; age: 19.7 ± 0.4 years; height: 182.6 ± 1.2 cm; weight: 75.9 ± 0.6kg) completed three randomly assigned trials; two prior to the supplementation period and one immediately after supplementation. The period between the first and the second trial was used as a control period and all subjects (n=20) participated. During the supplementation period the ribose group (n=10) received 20 g of ribose per day, while the placebo group (n=10) received 20 g of dextrose. The first day involved body composition, swim bench, and swim power measurements. The second day a test set consisting of 15x45.8 m freestyle swimming was performed. A blood sample was obtained from the antecubical vein prior to the swim and 1 minute after the completion of the last repeat. Swimming performance during the test set showed significant improvements for either group from T1 to T3. (mean ± SE 27.44 ± 0.32 and 27.55 ± 0.26 for the ribose and placebo groups respectively at T1). The times at the end of the supplementation period were 27.33 ± 0.28 and 27.36 ± 0.22 seconds. No significantdifferences were reported in swim power or swim bench. Lactate, uric acid, ammonia, and hypoxanthine did not significantly change for either group between the trials. The results from the study suggest that swimming performance does not appear to be enhanced with the supplementation of ribose during exhaustive exercise in collegiate male swimmers.