OBJECTIVE: This study aimed to investigate the clinical and pathological features of leprosy bacillus-related neuropathy in different clinical stages. PATIENTS AND METHODS: Four patients confirmed to have leprosy between 2012 and 2020 were chosen as the primary study subjects. The patients' clinical data were retrospectively analyzed to investigate the clinical and pathological features of the different clinical types of leprosy. RESULTS: Each patient had a different degree of deformity. For instance, in Case 1, upon dermatological examination, the eyebrows were not falling off, and the face was slightly invaded. The great auricular nerve was thickened. and there were plaques on the back of the right hand with III-defined edges but no itching. No atrophy in the thenar or hypothenar was observed. though pain and a warm sensation were noted. The swelling of the right leg was accompanied by sensory abnormalities. Moreover, the bilateral ulnar nerves were swollen, and demyelination changes were observed upon nerve biopsy. A small number of granulomas were noted in the nerve interstitium. and the acid-fast staining was positive. Additionally, in Case 2, on dermatological examination, scars were observed on the front of the tibia, and large. reddish, symmetrically distributed patches were seen on the back. Satellite foci were visible as well. Contracture was observed in the little finger, and the ulnar nerve was damaged. Skin and nerve biopsy revealed leprosy bacillus via acid-fast staining. CONCLUSIONS: Early detection and treatment are important methods of preventing and reducing damage to peripheral nerve function in patients with leprosy.