- Reinsertion, contraceptive device V25.42
- Reiter's disease, syndrome, or urethritis 099.3 [711.1099.3
- Rejection
- Relapsing fever 087.9
- Relaxation
- Remains
- Remittent fever (malarial) 084.6
- Remnant
- Remote effect of cancer- see condition
- Removal (of)
- Ren
- Renal - see also condition
- Rendu-Osler-Weber disease or syndrome (familial hemorrhagic telangiectasia) 448.0
- Reninoma (M8361/1) 236.91
- Rénon-Delille syndrome 253.8
- Repair
- Replacement by artificial or mechanical device or prosthesis of (see also Fitting (of))
- Reprogramming
- Request for expert evidence V68.2
- Reserve, decreased or low
- Residual - see also condition
- Resistance, resistant (to)