Medical Organizations
- Royal Army Dental Corps (RADC)
- Royal Army Medical Corps (RAMC)
- Royal Army Veterinary Corps (RAVC)
- Royal Australasian College of Surgeons (RAGS)
- Royal Australian and New Zealand College of Psychiatrists (RANZCP)
- Royal Australian College of General Practitioners (RACGP)
- Royal Australian College of Obstetricians and Gynecologists (RACOG)
- Royal Australian College of Ophthalmologists (RACO)
- Royal Australian College of Physicians (RACP)
- Royal British Nurses' Association (RBNA)
- Royal Canadian Army Medical Corps (RCAMC)
- Royal College of Chiropractic Sports Sciences (Canada) (RCCSSC)
- Royal College of General Practitioners (RCGP)
- Royal College of Midwives (RCM)
- Royal College of Nursing (UK) (RCN)
- Royal College of Obstetricians and Gynaecologists (UK) (RCOG)
- Royal College of Physicians and Surgeons of Canada (RCPSC)
- Royal College of Physicians and Surgeons of Glasgow (RCPSG)
- Royal College of Physicians; Royal College of Psychiatrists (RCP)
- Royal College of Radiologists (UK) (RCR)
- Royal College of Science Association (UK) (RCSA)
- Royal College Of Speech & Language Therapists (RCSLT)
- Royal College of Surgeons (RCS)
- Royal College of Surgeons of Canada (RCSC)
- Royal College of Surgeons of Edinburgh (RCSEd)
- Royal College of Surgeons of England (RCSENG)
- Royal College of Surgeons of Ireland (RCSI)
- Royal College of Veterinary Surgeons (RCVS)
- Royal Entomological Society (RES)
- Royal Faculty of Physicians and Surgeons (UK) (RFPS)
- Royal Institute of Public Health (RIPH)
- Royal Microscopical Society (UK) (RMS)
- Royal National Institute of Blind People (RNIBP)
- Royal Society for Public Health (UK) (RSPH)
- Royal Society for the Protection and Care of Animals (RSPCA)
- Royal Society of Chemistry (RSC)
- Royal Society of Medicine (UK) (RSM)
- Russian American Medical Association (RAMA)
- Sacramento District Dental Society (SDDS)
- Sacro Occipital Research Society International (SORSI)
- San Antonio Breastfeeding Coalition (SABC)
- San Antonio District Dental Society (SADDS)
- San Diego County Dental Society (SDCDS)
- San Diego Psychological Association (SDPA)
- Sandplay Therapists of America (STA)
- San Fernando Valley Dental Society (SFVDS)
- San Gabriel Valley Dental Society (SGVDS)
- Santa Cruz County Chapter of the California Association of Marriage and Family Therapists (SC-CAMFT)
- Schizophrenia & Psychosis Action Alliance (S&PAA)
- Schweizerische Entomologische Gesellschaft; Swiss Entomological Society (SEG)
- Schweizerische Gesellschaft fur Gynakologie; Swiss Society of Gynecology (SGG)
- Schweizerische Gesellschaft fur Hamatologie; Swiss Society of Hematology (SGH)
- Schweizerische Gesellschaft fur Innere Medizin; Swiss Society of Internal Medicine (SGAIM)
- Schweizerische Gesellschaft fur Kardiologie; Swiss Society of Cardiology (SGK)
- Schweizerische Gesellschaft fur Klinische Chemie; Swiss Society of Clinical Chemistry (SGKC)
- Schweizerische Gesellschaft fur Medizinische Genetik; Swiss Society of Medical Genetics (SGMG)
- Schweizerische Gesellschaft fur Phlebologie; Swiss Society of Phlebology (SGP)
- Schweizerische Gesellschaft fur Radiologie und Nuklearmedizin; Swiss Society of Radiology and Nuclear Medicine (SGRNM)
- Schweizerische Gesellschaft fur Ultraschall in der Medizin und Biologie; Swiss Society of Ultrasound in Medicine and Biology (SGUMB )
- Schweizerische Gesellschaft fur Unfallmedizin und Berufskrankheiten; Swiss Society of Traumatology and Occupational Diseases (SGUB)
- Schweizerische Ophthalmologische Gesellschaft; Swiss Society of Ophthalmology (SOG)
- Schweizerische Rettungsflugwacht; Swiss Air-Rescue (SRFW)
- Schweizerisches Rotes Kreuz; Swiss Red Cross (SRK)
- Science Research Association (SRA)
- Scientific Instrument Research Association (UK) (SIRA)
- Scoliosis Research Society (SRS)
- Seattle Study Club (SSC)
- Second District Dental Society of New York (SDDSNY)
- Sexual Medical Society of North America (SMSNA)
- Sigma Theta Tau International Honor Society of Nursing (Sigma)
- Singapore Psychological Society (SPS)
- Sociedad Interamericana de Psicologia; Inter-American Society of Psychology (SIP)
- Societa` Italiana di Ginecologia e Ostetricia; Italian Society of Gynecology and Obstetrics (SIGO)
- Societa Italiana di Medicina Interna; Italian Society of Internal Medicine (SIMI)
- Societa Italiana di Radiologia e Medicina Nucleare; Italian Society of Radiology and Nuclear Medicine (SIRMN)
- Societas Europaea Physiologiae Clinicae Respiratoriae; European Society of Clinical Respiratory Physiology (SEPCR)
- Societe Beige de Pharmacologie; Belgian Society of Pharmacology (SOBELPHA)
- Societe Belgique de Radiologie; Belgian Society of Radiology (SBR)
- Societe Europeenne de Pneumologie; European Society of Pneumology (SEP)
- Societe Europeenne d'Hematologie; Sociedad Europea de Hematologia; European Society of Hematology (SEH)
- Societe Francaise de Chirurgie Infantile; French Society of Surgery in Children (SFCI)
- Societe Francaise d'Experimentation Animale; French Society of Experiments in Animals (SFEA)
- Societe Francaise d'Ophtalmologie; French Society of Ophthalmology (Paris) (SFO)
- Societe Internationale d'Acupuncture; International Society of Acupuncture (SIA)
- Societe Internationale de Biometrie; International Society of Biometry (SIB)
- Societe Internationale de Cardiologie; Internationale Society of Cardiology (SIC)
- Societe Internationale de Chirugie, Orthopedie et Traumatologie; Society of Surgery, Orthopedics, and Traumatology (SICOT)
- Societe Internationale de Chirurgie; International Society of Surgery (SIC)
- Societe Internationale de Gastro-Enterologie; Sociedad Internacional de Gastro-Enterologia; International Society of Gastroenterology (SIGE)
- Societe Internationale de la Lepre; International Leprosy Society (SIL)
- Societe Internationale de Limnologie; International Society of Limnology (SIL)
- Societe Internationale de Psychopathologie de !'Expression; International Society of Psychopathology of Expression (SIPE)
- Societe Internationale des Medecins Generales; International Society of General Practitioners (SIMG)
- Societe Internationale de Transfusion Sanguine; International Society for Blood Transfusion (SITS)
- Societe Internationale de Traumatologie et de Medecine Sport d'Hiver; International Society of Traumatology and Medicine in Winter Sports (SITEMSH)
- Societe Internationale d'Hematologie; International Society of Hematology (ISH)
- Societe Internationale d'Oncologie Pediatrique; International Society of Pediatric Oncology (SIOP)
- Societe Internationale d'Urologie; Sociedad Internacional de Urologia; International Society of Urology (SIU)
- Societe Internationale pour les Droits de l'Homme; Sociedad Internacional para los Derechos Humanos; International Society for Human Rights (ISHR)
- Societe Medicale Internationale d'Endoscopie et de Radio-Cinematographie; International Medical Society of Endoscopy and Cinematoradiography (SMER)