During formation of fungal mats of Cunninghamella sp., colchicine seemed to have no effect on the mycelial dry weight but increased the phosphorus and nitrate uptake only when present in 20 p.p.m. All treatments increased the organic phosphorus content and peptide fraction of the tissue medium systems. These phenomena were furthered by raising the concentration of the drug. Colchicine showed its inhibitory effects on protein synthesis only when administered in the high concentration. The mechanism of nitrate utilisation in presence of colchicine was also discussed.