Guava (Psidiumguajava) leaf powder was used as an adsorbent to remove a synthetic dye Coomassie Brilliant Blue. A two level full-factorial design of three factors namely, pH, adsorbent dosage and temperature were performed and the effects of each parameter was analysed by statistical techniques. A regression model was proposed and it was statistically significant. pH had a major negative effect on biosorption process and it had an interaction effect with temperature.