- Posttraumatic brain syndrome, nonpsychotic 310.2
- Postures, hysterical 300.11
- Postvaccinal reaction or complication - see Complications, vaccination
- Postvagotomy syndrome 564.2
- Postvalvulotomy syndrome 429.4
- Postvasectomy sperm count V25.8
- Potain's disease (pulmonary edema) 514
- Potain's syndrome (gastrectasis with dyspepsia) 536.1
- Pott's
- Potter's
- Pouch
- Pouchitis 569.71
- Poulet's disease 714.2
- Poultrymen's itch 133.8
- Poverty V60.2
- PPE (palmar plantar erythrodysesthesia) 693.0
- Prader-Labhart-Willi-Fanconi syndrome (hypogenital dystrophy with diabetic tendency) 759.81
- Prader-Willi syndrome (hypogenital dystrophy with diabetic tendency) 759.81
- Pre-AIDS - see Human immunodeficiency virus (disease) (illness) (infection)
- Pre-eclampsia (mild) 642.4
- Pre-syncope 780.2
- Preachers' voice 784.49