Chitosan is a copolymer containing randomly distributed glucosamine (GlcN) and N-acetyl glucosamine (GlcNAc) monomers. GlcN is the dominant monomer in chitosan (more than 60%). Chitosan is a valuable biopolymer, which is found in the cell wall of zygomycetes fungi such as Mucor indicus . The chitosan content in the cell wall of these fungi strongly depends on the cultivation conditions. To compare the chitosan production under various conditions, it is necessary to use of an accurate, easy and reproducible technique . Nowadays, different methods have been used for determination of chitosan in fungal cell wall. In this study, firstly, performance of the best available method was investigated. In this method, chitin and chitosan were converted to anhydromannose through subsequent reactions with sulfuric and nitrous acids. Then, anhydromannose was converted to its blue colored complex by reaction with 3-methyl-2-benzothiozolone-hydrazone-hydrochloride (MBTH) and Iron(III) chloride (FeCl 3 ). The amount of this complex was measured according to colorimetric method. However, the colored complex was not stable and its absorbance was reduced significantly over time. In contrast anhydromannose, before conversion to colored complex, was stable and concentration of this material was accurately measured employing high performance liquid chromatography (HPLC). Therefore, a new method was presented in this work for accurate and time independent analysis of cell wall. The next step of this thesis was changing the fungal cultivation conditions towards improvement of chitosan production in the cell wall of M. inidus . The new measuring method was used to investigate the effect of different morphologies of Mucor indicus on chitosan concentration in the cell wall. Results showed that cells with filamentous morphology had the highest amount of GlcN (0.46 g/g cell wall). In contrast, only half of this value was available in the cell wall of yeast like cells. Additionally, results showed that similarly the filamentous morphology had the highest amount of GlcNAc (0.18 g/g cell wall). In contrast, it was reduced by changing the morphology into mostly yeast-like and purely yeast-like forms. Moreover, filamentous morphology had the lowest amount of phosphate (0.06 g/g cell wall) while this wa increased by changing the morphology into mostly yeast-like and purely yeast-like forms. Interestingly, total phosphate and N-acetyl glucosamine in three morphology was nearly constant and equal to 24%.Therefore, the rest of experiments was done using filamentous form of cells. In the next step, effect of phosphate content on chitosan production by this morphology was investigated. Results showed that with increasing concentrations up to 0.5 g/l of potassium dihydrogen phosphate in the culture media, phosphate was entirely consumed by the fungus while at higher concentrations, a significant fraction of phosphate remained intact. In other words, despite significant increase in the amount of phosphate in the culture media, small changes were observed in the phosphate uptake by the fungus. Additionally, the major fraction of consumed phosphate was placed in the body of fungi while only trace amounts was stored in the cell wall (about 0.01 g/l). Results showed that in culture containing no potassium dihydrogen phosphate, the highest chitosan production was achieved. key words Mucor indicus , morphology, chitosan, HPLC, phosphate.