- Speakers' throat 784.49
- Specific, specified - see condition
- Speech
- Spells 780.39
- Spencer's disease (epidemic vomiting) 078.82
- Spens' syndrome (syncope with heart block) 426.9
- Sperm counts
- Spermatic cord - see condition
- Spermatocele 608.1
- Spermatocystitis 608.4
- Spermatocytoma (M9063/3)
- Spermatorrhea 608.89
- Sphacelus (see also Gangrene) 785.4
- Sphenoidal - see condition
- Sphenoiditis (chronic) (see also Sinusitis, sphenoidal) 473.3
- Sphenopalatine ganglion neuralgia 337.09
- Sphericity, increased, lens 743.36
- Spherocytosis (congenital) (familial) (hereditary) 282.0
- Spherophakia 743.36
- Sphincter - see condition
- Sphincteritis, sphincter of Oddi (see also Cholecystitis) 576.8
- Sphingolipidosis 272.7