- Rolling of head 781.0
- Romano-Ward syndrome (prolonged QT interval syndrome) 426.82
- Romanus lesion 720.1
- Romberg's disease or syndrome 349.89
- Roof, mouth - see condition
- Rosacea 695.3
- Rosary, rachitic 268.0
- Rose
- Rosen-Castleman-Liebow syndrome (pulmonary proteinosis) 516.0
- Rosenbach's erysipelatoid or erysipeloid 027.1
- Rosenthal's disease (factor XI deficiency) 286.2
- Roseola 057.8
- Ross river fever 066.3
- Rossbach's disease (hyperchlorhydria) 536.8
- Rossle-Urbach-Wiethe lipoproteinosis 272.8
- Rostan's asthma (cardiac) (see also Failure, ventricular, left) 428.1
- Rot
- Rot-Bernhardt disease 355.1
- Rotation
- Röteln 056.9
- Roth's disease or meralgia 355.1
- Roth-Bernhardt disease or syndrome 355.1