- Concretio cordis 423.1
- Concretion - see also Calculus
- Concussion (current) 850.9
- Condition - see also Disease
- Conduct disturbance (see also Disturbance, conduct) 312.9
- Condyloma NEC 078.10
- Confinement - see Delivery
- Conflagration - see also Burn, by site
- Conflict
- Confluent - see condition
- Confusion, confused (mental) (state) (see also State, confusional) 298.9
- Confusional arousals 327.41
- Congelation 991.9
- Congenital - see also condition
- Congestion, congestive (chronic) (passive)
- Congestive - see Congestion
- Conical
- Conjoined twins 759.4
- Conjugal maladjustment V61.10
- Conjunctiva - see condition
- Conjunctivitis (exposure) (infectious) (nondiphtheritic) (pneumococcal) (pustular) (staphylococcal) (streptococcal) NEC 372.30
- Conjunctivochalasis 372.81
