- Chromaffinoma (M8700/0) - see also Neoplasm, by site, benign
- Chromatopsia 368.59
- Chromhidrosis, chromidrosis 705.89
- Chromoblastomycosis 117.2
- Chromomycosis 117.2
- Chromophytosis 111.0
- Chromotrichomycosis 111.8
- Chronic - see condition
- Churg-Strauss syndrome 446.4
- Chyle cyst, mesentery 457.8
- Chylocele (nonfilarial) 457.8
- Chylomicronemia (fasting) (with hyperprebetalipoproteinemia) 272.3
- Chylopericardium (acute) 420.90
- Chylothorax (nonfilarial) 457.8
- Chylous
- Chyluria 791.1
- Cicatricial (deformity) - see Cicatrix
- Cicatrix (adherent) (contracted) (painful) (vicious) 709.2
- CIDP (chronic inflammatory demyelinating polyneuropathy) 357.81
- CIN I [cervical intraepithelial neoplasia I] 622.11
- CIN II [cervical intraepithelial neoplasia II] 622.12
- CIN III [cervical intraepithelial neoplasia III] 233.1