- Sylvatic yellow fever 060.0
- Sylvest's disease (epidemic pleurodynia) 074.1
- Symblepharon 372.63
- Symonds' syndrome 348.2
- Sympathetic - see condition
- Sympatheticotonia (see also Neuropathy, peripheral, autonomic) 337.9
- Sympathicoblastoma (M9500/3)
- Sympathicogonioma (M9500/3) - see Sympathicoblastoma
- Sympathoblastoma (M9500/3) - see Sympathicoblastoma
- Sympathogonioma (M9500/3) - see Sympathicoblastoma
- Symphalangy (see also Syndactylism) 755.10
- Symptoms, specified (general) NEC 780.99
- Sympus 759.89
- Synarthrosis 719.80
- Syncephalus 759.4
- Synchondrosis 756.9
- Synchysis (senile) (vitreous humor) 379.21
- Syncope (near) (pre-) 780.2
- Syncytial infarct - see Placenta, abnormal
- Syndactylism, syndactyly (multiple sites) 755.10
- Syndrome - see also Disease
- Synechia (iris) (pupil) 364.70
