Addiction [Drug Dependence] is generally regarded as a mental disorder which commonly has related complications affecting a patients physical, psychological and social functioning (i.e.bio-psycho-social model).There is now evidence supporting that genetic, neurobiological and environmental factors play a significant role in the aetiology of Addiction.The lifetime population prevalence of Addiction in most countries is reported around 5%;most people who develop Addiction do so during the second or third decades of life;further, the prevalence of other mental disorders within this population is reported to be around 80% or more.An increasing research focus on neurobiological processes in Addiction has led to an expansion of pharmacological treatments and medical interest in this condition.Many patients with Addiction will also develop significant chronic medical problems as a consequence of their Addiction;for example, a smoker who is Nicotine Dependent ["addicted"] is likely to develop at least some degree of lung disease and many Alcohol Dependent patients will develop related liver disease.It is therefore better to understand Addiction as an acquired disorder of brain function that is most commonly manifest as a chronic relapsing and remitting, co-morbid disease.Patients with Addiction and related co-morbidity pose significant problems for providers of treatment like physicians and psychiatrists.In some countries, the medical and/or psychiatric management of patients with Addiction has developed as a specialist area of clinical practice (i.e.Addiction Medicine).An aging population brings with it a higher burden from chronic disease (e.g.degenerative and age-related conditions etc), and a significant proportion of many forms of chronic diseases (e.g.arteriosclerosis, heart disease, chronic airways disease, cirrhosis, neuropathy, dementia etc) are associated with Addiction.The brain is the primary target for drugs of Addiction and drug Addiction can lead to brain injury that renders the treatment of Addiction itself more complex.The medical management of Addiction that is co-morbid with multiple physical and mental disorders poses difficulties for clinicians because such patients often have problems with medication adherence and commitment to necessary medical, psychiatric and other "lifestyle" interventions.Wagner has described an approach to the medical management of patients with complex (and often interacting) co-morbidities which became referred to as the "Chronic Disease Management" model.One of the favorable aspects of this Chronic Disease Management model is that this approach involves utilizing evidence-based treatments in a framework that can be better coordinated between the patient and the various health practitioners involved.More recently, such an approach to the management of Addiction has been proposed and is now slowly being adopted by many treatment systems and also into the curricula of medical schools teaching about the subject of Addiction.This paper describes Addiction as a chronic disease state for which the best treatment approach is most likely a "Chronic Disease Management" model.