- Claude Bernard-Horner syndrome (see also Neuropathy, peripheral, autonomic) 337.9
- Claude's syndrome 352.6
- Claudicatio venosa intermittens 453.8
- Claudication, intermittent 443.9
- Claustrophobia 300.29
- Clavus (infected) 700
- Clawfoot (congenital) 754.71
- Clawhand (acquired) 736.06
- Clawtoe (congenital) 754.71
- Clay eating 307.52
- Clay shovelers' fracture - see Fracture, vertebra, cervical
- Cleansing of artificial opening (see also Attention to artificial opening) V55.9
- Cleft (congenital) - see also Imperfect, closure
- Cleft hand (congenital) 755.58
- Cleidocranial dysostosis 755.59
- Cleidotomy, fetal 763.89
- Cleptomania 312.32
- Clérambault's syndrome 297.8
- Clergyman's sore throat 784.49
- Click, clicking
- Clifford's syndrome (postmaturity) 766.22
- Climacteric (see also Menopause) 627.2
