National and International Clinical Guideline websites:

World Health Organization (WHO)
http://www.who.int/publications/guidelines/en/index.html

Canadian Medical Association (CMA)
www.cma.ca/En/Pages/clinical-practice-guidelines.aspx

Canadian Pediatric Society
http://www.cps.ca/en/documents

Society of Obstetricians and Gynaecologists of Canada (SOGC)
http://www.sogc.org/guidelines/index_e.asp

Canadian Task Force on Preventative Healthcare
http://canadiantaskforce.ca/guidelines/all-guidelines/

College of Family Physicians of Canada ( List of all guideline groups in Canada)
http://cfpc.ca/ClinicalPracticeGuidelines/

National Guidelines Clearinghouse (USA)
http://guideline.gov/browse/by-topic.aspx

American College of Physicians (ACP)
http://www.acponline.org/clinical_information/guidelines/guidelines/

Michigan Quality Improvement Consortium(MQIC)
http://www.mqic.org/guidelines.htm

Institute for Clinical Systems Improvement (ICSI)(USA)
http://www.icsi.org/guidelines_and_more/

U.S Preventative Services Task Force (USPSTF)
http://www.uspreventiveservicestaskforce.org/recommendations.htm

American Academy of Pediatrics 
http://brightfutures.aap.org/3rd_Edition_Guidelines_and_Pocket_Guide.html

Centers for Disease Control and prevention (USA)
http://www.cdc.gov/DiseasesConditions/

National Institute for health and Clinical Excellence (UK)
http://guidance.nice.org.uk/index.jsp?action=find

National Clinical Guideline Centre
http://www.ncgc.ac.uk/Guidelines/

Royal Australian College of General Practitiners
http://www.racgp.org.au/your-practice/guidelines/ 

National Health and Medical Research Council (Australia)
http://www.clinicalguidelines.gov.au/browse.php?treePath=C&pageType=1&

Scottish Intercollegiate Guidelines Network (SIGN)
http://www.sign.ac.uk/guidelines/index.html

New Zealand Guidelines Group (no more in existance, but guidelines still available)
http://www.health.govt.nz/about-ministry/ministry-health-websites/new-zealand-guidelines-group