The comparative effects of chronic (28 days) consumption of kolanut and its active constituent, caffeine diets on locomotor behaviour, body weights, exploration, anxiety and fear related behaviours in Swiss mice were investigated. Adult Swiss mice (15-30 g body weight), were used for the study. The open field-maze was employed for the evaluation of locomotor behaviour. The light/dark transition box, the elevated plus-maze as well as the open field-maze were used for the evaluation of exploration, anxiety and fear related behaviours in Swiss white mice. Mice in the control group (n=10) were fed normal rodent chow, mice in the kolanut-fed group (n=10) were fed kola diet (25% wt/wt of rodent chow) for four weeks respectively. All animals were allowed free access to clean drinking water. Daily food intake, water intake and body weight change were also measured. The results revealed that chronic consumption of kolanut and caffeine diets respectively in mice caused decreased locomotor activities, decreased anxiety and fear related behaviours and also increased exploratory behaviour in mice.