Enzyme replacement therapy (ERT) with elosulfase alfa is the only approved therapy in Japan for patients with Morquio A syndrome, a lysosomal storage disorder inherited in an autosomal recessive fashion. The experience with ERT in severely affected, non-ambulatory patients has not been reported in previous studies. This case report describes clinical evidence for the 1-year efficacy and safety of ERT with elosulfase alfa in a severely affected, non-ambulatory, 47-year-old patient with Morquio A syndrome who needs intensive respiratory management. ERT with elosulfase alfa was well tolerated in this patient. Because of the possibility of potential hypersensitivity adverse events, special attention is needed when using ERT in patients with respiratory disorders. However, under the appropriate management of specialists, the patient in this case report showed significant respiratory improvement after starting ERT, and abdominal bloating was improved by gas evacuation. In addition, the patient was able to lift up her arms, reach behind her back, and move her legs slightly, and she recovered her grip strength. Her hearing loss improved and she could hear without a hearing aid. This report shows that ERT with elosulfase alfa can be used with appropriate respiratory care in patients with severe respiratory dysfunction.