This paper present results of the research aimed at isolating fungi strains which exposed high Chitinase activity and at studying the medium conditions affecting chitinase production of a chosen fungi straiin. By determination of the halo's diameters of colonies on culture medium with chitin as a specific substrate, ten fungi strains with high chitinase activity were isolated. Among isolated, one strain with highest chitinase production was selected. This strain was morphologically and biomolecularly determined as Penicillium oxalicum. The suitable conditions for high chitinase production of Penicillium oxalicum were as follows: Humidity of 80 percent, chitin of 10 percent, sodium chloride of 2 percent, 48 h incubation, pH of 4,5 and temperature of 40°C. Also, the interaction of three factors such as pH, temperature, and incubation time were studied. The optimum conditions were defined as follows: Humidity of 84 percent, pH of 4,1 and temperature of 36°C.