- Glanzmann (-Naegeli) disease or thrombasthenia 287.1
- Glassblowers' disease 527.1
- Glaucoma (capsular) (inflammatory) (noninflammatory) (primary) 365.9
- Glaucomatous flecks (subcapsular) 366.31
- Glazed tongue 529.4
- Gleet 098.2
- Glénard's disease or syndrome (enteroptosis) 569.89
- Glinski-Simmonds syndrome (pituitary cachexia) 253.2
- Glioblastoma (multiforme) (M9440/3)
- Glioma (malignant) (M9380/3)
- Gliomatosis cerebri (M9381/3) 191.0
- Glioneuroma (M9505/1) - see Neoplasm, by site, uncertain behavior
- Gliosarcoma (M9380/3)
- Gliosis (cerebral) 349.89
- Glisson's
- Glissonitis 573.3
- Globinuria 791.2
- Globus 306.4
- Glomangioma (M8712/0) (see also Hemangioma) 228.00
- Glomangiosarcoma (M8710/3) - see Neoplasm, connective tissue, malignant
- Glomerular nephritis (see also Nephritis) 583.9
- Glomerulitis (see also Nephritis) 583.9