Microcrystalline cellulose (MCC) was isolated from papaya stem, characterized and compared with a commercial brand MCC. The dried pulverized papaya stem was subjected to alkaline treatment using aqueous NaOH and NaOCl solutions. Alpha cellulose obtained was modified by partial hydrolysis using 2.5 M HCl at boiling temperature to produce microcrystalline cellulose. The Physicochemical properties such as bulk, tapped and true densities, degree of polymerization, particle sizes, moisture content, angle of repose etc were examined and compared with a commercial brand sample (C-MCC). Results have shown that the percentage yields of alpha cellulose and CU-MCC obtained from the starting dried stem material were 23.78 and 20.70, respectively. Fourier Transform Infrared (FT-IR) spectra of CU-MCC and C-MCC confirmed the presence of OH and (C=O) carbonyl functional group which are the main characteristics of cellulose. Scanning Electron Microscopy (SEM) showed individual rod-like and flat-shaped plank-like fiber structures with few bundled crystal packed forms for the CU-MCC and C-MCC respectively. The C-MCC has a high thermal stability at 408°C when compared to 367°C of the hydrolysed CU-MCC. This may be resulting from the morphological characteristics of the fiber structures. CU-MCC had poor powder flow properties and an appreciable thermal resistance.