I. E. Orji, M. J. Eka, P. I. Okocha , J. C. Harriman Colchicine, mutagenesis, sodium azide, sweetpotato, root formation 33-37 5 (2) 2021 April,2021 Field experiments were conducted with the aim of establishing the influence of chemical induced mutagenesis on percentage storage root formation of four varieties of sweetpotato in the M₁V₁ and M₂V₂ generations. Vine cuttings obtained were soaked in Sodium Azide (SA) and Colchicine (COL) mutagens at various concentrations: 0%, 0.03%, 0.05% and 0.07%, for 2 hours. The experiment was laid out using a split-plot arrangement fitted into a Randomized Complete Block Design and replicated three times. For the sodium azide treatments, percentage storage root formation reduced as the mutagen concentration increased; while for the colchicine treatments, COL 0.00% tubered more than the other concentrations in the M₁V₁ generation. In the M₂V₂ generation though no significant difference was observed between SA 0.00%, SA 0.03%, and SA 0.05% among the sodium azide treatments; there was a decrease in percentage storage root formation among the colchicine treatments as the concentration increased. The result in this research suggested that the formation of storage roots in varieties of sweetpotato used in the study was affected to different extents by chemical mutagens. It may therefore be necessary to compare the effects of different mutagens on yield parameters of different varieties of sweetpotato to arrive at a dosage that can exert a maximum variability for selection of useful traits.