Among patients with mental health and addiction (MHA) disorders, smoking prevalence is greater, being as much as two to four times higher than that found in the general population. More than 2/3 of the individuals with some severe MHA disorders, such as schizophrenia and heroin dependence, are daily smokers. This may be one reason why patients with MHA disorders die 25 years before the general population. Numerous biological, psychological and social factors may explain these high rates of smoking, including, for example, lack of smoking cessation intervention in MHA environments or even the use of tobacco for self-medication of psychiatric symptoms. It has been recommended that smokers with MHA disorders use the same smoking cessation treatments as the general population but in a more intensive and monitored way, since they usually have higher levels of nicotine dependence and use other medication. Pharmacological and psychotherapy interactions may occur at some point, and the core symptoms of tobacco withdrawal are frequently confused with previous MHA disorder. Because of that, primary care clinicians rarely feel comfortable to provide them smoking cessation treatment. Smoking epidemiology, aetiology, assessment and treatment for individuals with MHA disorders are going to be discussed in this presentation.