- Polyuria 788.42
- Pompe's disease (glycogenosis II) 271.0
- Pompholyx 705.81
- Poncet's disease (tuberculous rheumatism) (see also Tuberculosis) 015.9
- Pond fracture - see Fracture, skull, vault
- Ponos 085.0
- Pons, pontine - see condition
- Poor
- Poradenitis, nostras 099.1
- Porencephaly (congenital) (developmental) (true) 742.4
- Porocephaliasis 134.1
- Porokeratosis 757.39
- Poroma, eccrine (M8402/0) - see Neoplasm, skin, benign
- Porphyria (acute) (congenital) (constitutional) (erythropoietic) (familial) (hepatica) (idiopathic) (idiosyncratic) (intermittent) (latent) (mixed hepatic) (photosensitive) (South African genetic) (Swedish) 277.1
- Porphyrinuria (acquired) (congenital) (secondary) 277.1
- Porphyruria (acquired) (congenital) 277.1
- Port wine nevus or mark 757.32
- Portal - see condition
- Posadas-Wernicke disease 114.9
- Position
- Positive
- Post-dates (pregnancy) - see Pregnancy