- Leptomeningitis (chronic) (circumscribed) (hemorrhagic) (nonsuppurative) (see also Meningitis) 322.9
- Leptomeningopathy (see also Meningitis) 322.9
- Leptospiral - see condition
- Leptospirochetal - see condition
- Leptospirosis 100.9
- Leptothricosis - see Actinomycosis
- Leptothrix infestation - see Actinomycosis
- Leptotricosis - see Actinomycosis
- Leptus dermatitis 133.8
- Léri-Weill syndrome 756.59
- Leriche's syndrome (aortic bifurcation occlusion) 444.0
- Léris pleonosteosis 756.89
- Lermoyez's syndrome (see also Disease, Ménière's) 386.00
- Lesbianism - omit code
- Lesch-Nyhan syndrome (hypoxanthine-guanine-phosphoribosyltransferase deficiency) 277.2
- Lesion(s)
- Lethargic - see condition
- Lethargy 780.79
- Letterer-Siwe disease (acute histiocytosis X) (M9722/3) 202.5
- Leucinosis 270.3
- Leucocoria 360.44
- Leucosarcoma (M9850/3) 207.8
