Herein, we report the manifestation of type 1A Charcot-Marie-Tooth disease(CMT)in a 54-year-old female gastric cancer patient caused by oxaliplatin(L-OHP)of neoadjuvant chemotherapy containing S-1 plus L-OHP(G-SOX). In this case, peripheral sensory neuropathy(PSN)appeared in both upper limbs immediately after the administration of L-OHP. Subsequently, we observed sensory neuropathy of gloves-socks type in both the upper and lower limbs and motor neuropathy in both lower limbs, which caused the patient to be unable to sit up. Physical examination revealed upside-down champagnebottle- like mild atrophy in both lower limbs and hollow feet in both legs, as well as the disappearance of deep tendon reflexes in both lower limbs. In her family history, her eldest daughter had undergone Achilles tendon elongation surgery for suspected CMT at the age of 3 years. Considering these, she was suspected to have CMT and was finally diagnosed with type 1A CMT based on genetic testing. In anti-cancer treatments that cause PSN(not just by L-OHP), possible involvement of occult peripheral nerve disease like CMT should be considered when more rapid and untypical PSN appears after the administration of anti-cancer drugs.