Fungal chitosan is highly demanded because of its better physico-chemical characteristics compared to crustaceans' chitosan. In the current study, a marine-derived fungus was isolated from the Mediterranean Sea in Egypt and was identified according to microscopic and molecular characteristics of Penicillium chrysogenum MZ723110. The fungal strain was used for chitosan extraction. The resultant chitosan was characterized by Fourier transform infrared spectroscopy (FT-IR) analysis and the degree of deacetylation (DD%). Statistical optimization of fungal growth conditions for maximum chitosan yield was done using Plackett Burman design (PBD) and central composite design (CCD). The statistical optimization revealed that the type of fungal culture, peptone concentration, and incubation period were the most significant factors. Upon their optimization, there was a 3.1-fold increase in chitosan yield by P. chrysogenum MZ723110. The yield of chitosan was increased from 4.4% to 7.5 % with DD% equal to 94%. The results of this study proved the importance of optimizing fungal growth conditions for the maximum yield of chitosan.