This research focuses on the extraction and characterisation of chitin and chitosan from fungal biomass, Termitomyces titanicus, by immersing it in a solution of sodium hydroxide, followed by deacetylation in a basic medium using the full two-level factorial design (2 2) to obtain chitosan as a residual. The obtained chitosan was characterised by basic conductimetric titration and viscometry to determine the degree of deacetylation and the average molecular weight, respectively. The extraction of chitin was carried out under the following operating conditions: particle size less than 2.5 mm; hydrolysis time of 120 min; concentration 3 M of the NaOH solution; and temperature of 100 °C. The extraction yield of chitin was 38.04%, and the degree of deacetylation of chitosan was 69.50%, an intrinsic viscosity of 0.6822 dL/g, and a viscosimetric average molecular weight of 985.88 kDa. This research therefore shows that fungus specie called T. titanicus can serve as an alternative chitin and chitosan source. In addition, the mathematical model established for deacetylation degree that, based upon the extra process time, it would be possible to increase the purity of chitosan.