Kolanut (Cola nitida) seed is rich in caffeine which could be as high as 51% (Salahdeen et al; 2015). In view of the reported insulin insensitivity caused by caffeine (Urzua et al; 2012), this study investigated the effects of acute and chronic administrations of ethanolic extract of Kolanut (EEK) seed on glucose tolerance of rats. Male albino Wistar rats (250 – 300gm) and divided into three groups (I, II and III) with 8 rats per group were studied. Group I was orally administered distilled water (control). Group II had acute oral administration of EEK (6mg/kg), while group III was orally administered EEK (6mg/kg) for eight weeks. Blood samples (0.2ml per sample from distal end of the tail) and liver biopsies were taken to determine plasma glucose and serum insulin levels, liver glycogen, liver glycogen synthase and phosphorylase activities. Blood glucose was determined by glucose oxidase method. Oral glucose tolerance test was carried out on each rat. Plasma glucose concentrations were plotted as a function of time and areas under glucose curve (AUGs) calculated. Glycogen level was determined by anthrone method. Radioimmunoassay kit (diagnostic product) was used to determine the serum insulin level. Values are mean + S.E.M, compared by ANOVA and Student t-test. AUG increased by 35% for acute group and decreased by 28% for chronic group. Peak serum insulin also increased by 18% for acute group and was reduced by 15% for the chronic group. There were no significant changes in liver glycogen and activities of glycogen synthase and phosphorylase in acute condition. However, in chronic group, the liver glycogen and the activity of glycogen increased significantly. There was also a significant decrease in phosphorylase activity. The results suggest that the effects of EEK following acute and chronic administrations are not the same. While acute intake produced glucose intolerance, chronic intake improves glucose tolerance.