- Tamponade heart (Rose's) (see also Pericarditis) 423.9
- Tanapox 078.89
- Tangier disease (familial high-density lipoprotein deficiency) 272.5
- Tank ear 380.12
- Tantrum (childhood) (see also Disturbance, conduct) 312.1
- Tapeworm (infection) (infestation) (see also Infestation, tapeworm) 123.9
- Tapia's syndrome 352.6
- Tarantism 297.8
- Target-oval cell anemia 282.49
- Tarlov's cyst 355.9
- Tarral-Besnier disease (pityriasis rubra pilaris) 696.4
- Tarsal tunnel syndrome 355.5
- Tarsalgia 729.2
- Tarsitis (eyelid) 373.00
- Tartar (teeth) 523.6
- Tattoo (mark) 709.09
- Taurodontism 520.2
- Taussig-Bing defect, heart, or syndrome (transposition, aorta and overriding pulmonary artery) 745.11
- Tay's choroiditis 363.41
- Tay-Sachs
- Taybi's syndrome (otopalatodigital) 759.89
- Taylor's
