Abstract: The antinutritional components of five hybrid varieties of water yam (Dioscorea alata) and two land races were evaluated. The antinutritional factors evaluated were phenol ranging from 0.16 to 0.27%; hydrogen cyanide, 9.62 to 12.00 mg/kg; alkaloids, 0.12 to 0.55%; tanmins, 46.50 to 180.25%; phytate, 0.22 to 0.28%; heamagglutinin, 1.22 to 5.75 Hu/g and trypsin inhibitor, 24.02 to 49.51. TI unit/mg. There were significant differences (P < 0.05) in some of the antinutritional factors among the water yam varieties investigated. Generally most of antinutritional factors are low to cause health hazard. The overall results are suggestive of high nutritional quality of the water yam varieties due to low presence of antinutritional factors compared to other tropical root crops.