- Translocation
- Translucency, iris 364.53
- Transmission of chemical substances through the placenta (affecting fetus or newborn) 760.70
- Transplant (ed)
- Transplants, ovarian, endometrial 617.1
- Transposed - see Transposition
- Transposition (congenital) - see also Malposition, congenital
- Transverse - see also condition
- Transvestism, transvestitism (transvestic fetishism) 302.3
- Trapped placenta (with hemorrhage) 666.0
- Trauma, traumatism (see also Injury, by site) 959.9
- Traumatic - see condition
- Treacher Collins' syndrome (incomplete facial dysostosis) 756.0
- Treitz's hernia - see Hernia, Treitz's
- Trematode infestation NEC 121.9
- Trematodiasis NEC 121.9
- Trembles 988.8
- Trembling paralysis (see also Parkinsonism) 332.0
- Tremor 781.0
- Trench
- Treponema pallidum infection (see also Syphilis) 097.9
- Treponematosis 102.9