- Water-losing nephritis 588.89
- Waterbrash 787.1
- Waterhouse (-Friderichsen) disease or syndrome 036.3
- Watermelon stomach 537.82
- Wax in ear 380.4
- Waxy
- Weak, weakness (generalized) 780.79
- Wear, worn, tooth, teeth (approximal) (hard tissues) (interproximal) (occlusal) - see also Attrition, teeth 521.10
- Weather, weathered
- Web, webbed (congenital) - see also Anomaly, specified type NEC
- Weber's paralysis or syndrome 344.89
- Weber-Christian disease or syndrome (nodular nonsuppurative panniculitis) 729.30
- Weber-Cockayne syndrome (epidermolysis bullosa) 757.39
- Weber-Dimitri syndrome 759.6
- Weber-Gubler syndrome 344.89
- Weber-Leyden syndrome 344.89
- Weber-Osler syndrome (familial hemorrhagic telangiectasia) 448.0
- Wedge-shaped or wedging vertebra (see also Osteoporosis) 733.00
- Wegener's granulomatosis or syndrome 446.4
- Wegner's disease (syphilitic osteochondritis) 090.0
- Weight
- Weightlessness 994.9