- Wet
- Wharton's duct - see condition
- Wheal 709.8
- Wheelchair confinement status V46.3
- Wheezing 786.07
- Whiplash injury or syndrome 847.0
- Whipple's disease or syndrome (intestinal lipodystrophy) 040.2
- Whipworm 127.3
- White - see also condition
- White's disease (congenital) (keratosis follicularis) 757.39
- Whitehead 706.2
- Whitlow (with lymphangitis) 681.01
- Whitmore's disease or fever (melioidosis) 025
- Whooping cough 033.9
- Wichmann's asthma (laryngismus stridulus) 478.75
- Widal (-Abrami) syndrome (acquired hemolytic jaundice) 283.9
- Widening aorta (see also Ectasia, aortic) 447.70
- Wilkie's disease or syndrome 557.1
- Wilkinson-Sneddon disease or syndrome (subcorneal pustular dermatosis) 694.1
- Willan's lepra 696.1
- Willan-Plumbe syndrome (psoriasis) 696.1
- Willebrand (-Jürgens) syndrome or thrombopathy (angiohemophilia) 286.4