- Genetic
- Genital - see condition
- Genito-anorectal syndrome 099.1
- Genitourinary system - see condition
- Genu
- Geographic tongue 529.1
- Geophagia 307.52
- Geotrichosis 117.9
- Gephyrophobia 300.29
- Gerbode defect 745.4
- GERD (gastroesophageal reflux disease) 530.81
- Gerhardt's
- Gerlier's disease (epidemic vertigo) 078.81
- German measles 056.9
- Germinoblastoma (diffuse) (M9614/3) 202.8
- Germinoma (M9064/3) - see Neoplasm, by site, malignant
- Gerontoxon 371.41
- Gerstmann's syndrome (finger agnosia) 784.69
- Gerstmann-Sträussler-Scheinker syndrome (GSS) 046.71
- Gestation (period) - see also Pregnancy
- Gestational proteinuria 646.2
- Ghon tubercle primary infection (see also Tuberculosis) 010.0
