- Barlow (-Möller) disease or syndrome (meaning infantile scurvy) 267
- Barlow's syndrome (meaning mitral valve prolapse) 424.0
- Barodontalgia 993.2
- Baron Münchausen syndrome 301.51
- Barosinusitis 993.1
- Barotitis 993.0
- Barotrauma 993.2
- Barraquer's disease or syndrome (progressive lipodystrophy) 272.6
- Barré-Guillain syndrome 357.0
- Barré-Liéou syndrome (posterior cervical sympathetic) 723.2
- Barrel chest 738.3
- Barrett's esophagus 530.85
- Barrett's syndrome or ulcer (chronic peptic ulcer of esophagus) 530.85
- Bársony-Polgár syndrome (corkscrew esophagus) 530.5
- Bársony-Teschendorf syndrome (corkscrew esophagus) 530.5
- Barth syndrome 759.89
- Bartholin's
- Bartholinitis (suppurating) 616.89
- Bartonellosis 088.0
- Bartter's syndrome (secondary hyperaldosteronism with juxtaglomerular hyperplasia) 255.13
- Basal - see condition
- Basan's (hidrotic) ectodermal dysplasia 757.31