| Abbreviations | Meaning |
 | LAMSO | Life And Medical Sciences Online [periodical] |
 | LAN | Laboratory Automation News |
 | LAS | Laboratory And Point-of-Care Testing Accreditation Standards |
 | LASA | Laboratory Animal Science Association |
 | LASS | Latin American Sleep Society |
 | LATRA | LAboratoire De Transcription Et De Recherches Pour Aveugles Et Amblyopes |
 | LAVA | Laboratory Animal Veterinary Association |
 | LCA | Lung Cancer Alliance |
 | LCCE / CLAE | Ligue Canadienne Contre L'épilepsie / Canadian League Against Epilepsy |
 | LCCH | London College Of Clinical Hypnosis |
 | LCH | Langerhans Cel Histiocytose Belgium. L'Histiocytose De Langerhans |
 | LCMHA | Lenawee Community Mental Health Authority |
 | LDA | Learning Disabilities Association |
 | LDA | Louisiana Dental Association |
 | LDAC | Learning Disabilities Association Of Canada. Troubles D'Apprentissage - Association Canadienne |
 | LDB | Genetic Location Database |
 | LDHA | Louisiana Dental Hygienists Association |
 | LDRR | Laboratory Of Diagnostic Radiology Research |
 | LE GOëLAND | Association Nationale Du Syndrome X Fragile |
 | LEAD | Lead Education Abatement Design Group |
 | LEF | Life Extension Foundation |
 | LFA | Lupus Foundation Of America |
 | LFC / FCL | Lymphoma Foundation Canada / Fondation Canadienne Sur Le Lymphome [Previously: Lymphoma Research Foundation Canada (LRFC) / Fondation Canadienne De Recherche Sur Le Lymphome (FCRL)] |
 | LFCD | Ligue Française Contre La Dystonie |
 | LFCE | Ligue Française Contre L'Épilepsie |
 | LFCN | Ligue Française Contre Les Neurofibromatoses |
 | LFN | Libraries For Nursing |
 | LGVMA | Lesbian & Gay Veterinary Medical Association |
 | LHNCBC | Lister Hill National Center For Biomedical Communications |
 | LIDHA | Long Island Dental Hygienists Association |
 | LIMBIO | Laboratoire D'Imagerie Moléculaire Et Bioinformatique / Molecular Imaging And Bioinformatics Laboratory |
 | LIMNURP | Lippincott Manual Of Nursing Practice |
 | LINK | WHO Library And Information Networks For Knowledge. Bibliothèque Et Réseaux D'information à L'appui Des Connaissances De L'OMS |
 | LJI | List Of Journals Indexed In Index Medicus |
 | LLBA | Linguistics And Language Behavior Abstracts |
 | LLCC | Ligue Luxembourgeoise Contre Le Cancer |
 | LLL | La Leche League |
 | LLLI | La Leche League International |
 | LLLT | Low Level Laser Therapy |
 | LMSA | Latino Medical Student Association |
 | LNC | Legal Nurse Consultant |
 | LNCC | Ligue Nationale Contre Le Cancer |
 | LOCIS | Library Of Congress Information System |
 | LOEX | Laboratoire D'Organogénèse Expérimentale. Laboratory Of Experimental Tissue Engineering |
 | LONI | Library Of Neuropsychological Information |
 | LOPEX | Laboratoire D'Orthopédogénèse Expérimentale |
 | LOPNEX | Laboratoire D'Organogénèse Pneumologique Expérimentale |
 | LRDT | Laboratory Of Reproductive And Developmental Toxicology |
 | LRF | Leukemia Research Foundation |
 | LRF | Lymphoma Research Foundation |