- Stromatosis, endometrial (M8931/1) 236.0
- Strong pulse 785.9
- Strongyloides stercoralis infestation 127.2
- Strongyloidiasis 127.2
- Strongyloidosis 127.2
- Strongylus (gibsoni) infestation 127.7
- Strophulus (newborn) 779.89
- Struck by lighting 994.0
- Struma (see also Goiter) 240.9
- Strumipriva cachexia (see also Hypothyroidism) 244.9
- Strümpell-Marie disease or spine (ankylosing spondylitis) 720.0
- Strümpell-Westphal pseudosclerosis (hepatolenticular degeneration) 275.1
- Stuart's disease (congenital factor X deficiency) (see also Defect, coagulation) 286.3
- Stuart-Prower factor deficiency (congenital factor X deficiency) (see also Defect, coagulation) 286.3
- Students' elbow 727.2
- Stuffy nose 478.19
- Stump - see also Amputation
- Stupor 780.09
- Sturge (-Weber) (-Dimitri) disease or syndrome (encephalocutaneous angiomatosis) 759.6
- Sturge-Kalischer-Weber syndrome (encephalocutaneous angiomatosis) 759.6
- Stuttering 307.0
- Sty, stye 373.11