Two forms of invertase, isolated from Fusarium oxysporum, were designated P-1 and P-2 enzymes according to their respective elution profiles on DEAE-cellulose column. P-1 was produced mainly at an early stage in the cell culture and P-2 was produced at a late stage and its production agreed with the appearance of microconidia. Mycelia separated from microconidia contained only P-1. Optimum pH, substrate specificity, and transferase activity of P-1 enzyme were somewhat different from those of P-2 enzyme. Invertase (M) secreted into the medium at a late stage in the culture showed similar properties to P-2 enzyme. All three enzymes contained carbohydrates and showed β-fructofuranosidase activity. P-1 and P-2 enzymes were both inhibited by Ca2 + Zn2 + and Cu2+ but not by Ni2+ and Co2+. © 1979, Applied Microbiology, Molecular and Cellular Biosciences Research Foundation. All rights reserved.