- Choreoathetosis (paroxysmal) 333.5
- Chorioadenoma (destruens) (M9100/1) 236.1
- Chorioamnionitis 658.4
- Chorioangioma (M9120/0) 219.8
- Choriocarcinoma (M9100/3)
- Chorioencephalitis, lymphocytic (acute) (serous) 049.0
- Chorioepithelioma (M9100/3) - see Choriocarcinoma
- Choriomeningitis (acute) (benign) (lymphocytic) (serous) 049.0
- Chorionepithelioma (M9100/3) - see Choriocarcinoma
- Chorionitis (see also Scleroderma) 710.1
- Chorioretinitis 363.20
- Choristoma - see Neoplasm, by site, benign
- Choroid - see condition
- Choroideremia, choroidermia (initial stage) (late stage) (partial or total atrophy) 363.55
- Choroiditis (see also Chorioretinitis) 363.20
- Choroidopathy NEC 363.9
- Choroidoretinitis - see Chorioretinitis
- Choroidosis, central serous 362.41
- Choroidretinopathy, serous 362.41
- Christian's syndrome (chronic histiocytosis X) 277.89
- Christian-Weber disease (nodular nonsuppurative panniculitis) 729.30
- Christmas disease 286.1