- Sturge (-Weber) (-Dimitri) disease or syndrome (encephalocutaneous angiomatosis) 759.6
- Sturge-Kalischer-Weber syndrome (encephalocutaneous angiomatosis) 759.6
- Stuttering 315.35
- Sty, stye 373.11
- Subacidity, gastric 536.8
- Subacute - see condition
- Subarachnoid - see condition
- Subclavian steal syndrome 435.2
- Subcortical - see condition
- Subcostal syndrome 098.86
- Subcutaneous, subcuticular - see condition
- Subdelirium 293.1
- Subdural - see condition
- Subendocardium - see condition
- Subependymoma (M9383/1) 237.5
- Suberosis 495.3
- Subglossitis - see Glossitis
- Subhemophilia 286.0
- Subinvolution (uterus) 621.1
- Sublingual - see condition
- Sublinguitis 527.2
- Subluxation - see also Dislocation, by site