- G-trisomy 758.0
- Gafsa boil 085.1
- Gain, weight (abnormal) (excessive) (see also Weight, gain) 783.1
- Gaisböck's disease or syndrome (polycythemia hypertonica) 289.0
- Gait
- Galactocele (breast) (infected) 611.5
- Galactophoritis 611.0
- Galactorrhea 676.6
- Galactosemia (classic) (congenital) 271.1
- Galactosuria 271.1
- Galacturia 791.1
- Galen's vein - see condition
- Gall duct - see condition
- Gallbladder - see also condition
- Gallop rhythm 427.89
- Gallstone (cholemic) (colic) (impacted) - see also Cholelithiasis
- Gambling, pathological 312.31
- Gammaloidosis 277.39
- Gammopathy 273.9
- Gamna's disease (siderotic splenomegaly) 289.51
- Gampsodactylia (congenital) 754.71
- Gamstorp's disease (adynamia episodica hereditaria) 359.3