- Osteo-onychodysplasia, hereditary 756.89
- Osteoarthritica spondylitis (spine) (see also Spondylosis) 721.90
- Osteoarthritis (see also Osteoarthrosis) 715.9
- Osteoarthropathy (see also Osteoarthrosis) 715.9
- Osteoarthrosis (degenerative) (hypertrophic) (rheumatoid) 715.9
- Osteoblastoma (M9200/0) - see Neoplasm, bone, benign
- Osteochondritis (see also Osteochondrosis) 732.9
- Osteochondrodermodysplasia 756.59
- Osteochondrodystrophy 277.5
- Osteochondrolysis 732.7
- Osteochondroma (M9210/0) - see also Neoplasm, bone, benign
- Osteochondromatosis (M9210/1) 238.0
- Osteochondromyxosarcoma (M9180/3) - see Neoplasm, bone, malignant
- Osteochondropathy NEC 732.9
- Osteochondrosarcoma (M9180/3) - see Neoplasm, bone, malignant
- Osteochondrosis 732.9
- Osteoclastoma (M9250/1) 238.0
- Osteocopic pain 733.90
- Osteodynia 733.90
- Osteodystrophy
- Osteofibroma (M9262/0) - see Neoplasm, bone, benign
- Osteofibrosarcoma (M9182/3) - see Neoplasm, bone, malignant
