The annual rate of ipsilateral stroke associated with asymptomatic carotid stenosis has fallen from 2-4% to <1% in the last 20 years due to improvements in medical therapy. The fundamental benefits of this are relevant to whether patients undergo revascularisation or not. We aimed to evaluate existing international guidelines for the management of carotid stenosis, identifying important similarities and differences. The websites of the American Heart Association, Society for Vascular Surgery, European Society for Cardiology, European Society for Vascular Surgery, British Cardiovascular Society and UK Vascular Society were searched for guidelines relating to primary prevention for asymptomatic atherosclerotic carotid disease in September 2011 and independently reviewed by 2 authors. The following guidelines were identified and compared: The Joint British Societies 2nd (JBS2) 2005 guideline, the 4th European Society for Cardiology (ESC) 2007 guideline, the joint American Heart Association/Society for Vascular Surgery (AHA/SVS) guideline 2011 and subsequent 2011 SVS update, the American Heart Association (AHA) prevention of stroke guideline 2010, the AHA secondary prevention for atherosclerotic coronary and vascular disease 2011 update, and the European Society for Vascular Surgery (ESVS) Section A carotid guideline. There was no UK guidance from its vascular society. Important differences were evident in methods of risk assessment, treatment targets for blood pressure and low density lipoprotein cholesterol, and the use of anti-platelet agents. These differences are highlighted in 2 case scenarios. There is now clear, evidence based guidance from British, European and US cardiovascular bodies regarding optimal targets for risk factor modification. These can be adopted as standard operating procedure for clinical practice and the medical arms of carotid interventional trials. In the future imaging biomarkers may help provide an understanding of the risk of an individual carotid lesion to help guide therapy.