Background: Treatment of patients with chronic conditions requiring hospitalization requires patient acceptance and cooperation and adoption of coping strategies. Inappropriate coping strategies such as substance abuse are concerning in the course of treatment. This study sought to explore the association of coping strategies with suicidal behavior in substance abusers and non substance abuser patients with chronic pulmonary diseases namely asthma and chronic obstructive pulmonary disease (COPD). Materials and Methods: This comparative study was performed on 100 patients with asthma and COPD selected via convenience sampling. Subjects with and without substance abuse were separated into two groups of 50 patients each. Ways of Coping Questionnaire of Lazarus (WOCQ) and Suicide Behavior Questionnaire-Revised (SBQ-R) were completed by them. Five Persian speaking patients rated this questionnaire to be easily understandable in the pre-test stage. Cronbach's alpha was calculated to measure the internal consistency. Results: The mean (±standard deviation) age of participants was 40 (±14) years; 58% of individuals were men; 62% had chosen problem-focused coping. The most abused substances were cigarettes (78%) and opium (42%); 6% of substance abusers had thought about suicide five times or more in the past year; 5% of substance abusers had seriously attempted suicide. Tendency to commit suicide was greater in men, substance abusers and participants who had chosen emotion-focused coping strategies, based on a regression model. Average score of suicide tendency was significantly higher in substance abusers (B=2.196, P =0.007). Conclusion: Chronic disease is a crisis and patients need to acquire appropriate coping strategies to deal with it, especially in substance abusers and suicidal patients. Precise recognition of coping strategies in chronic pulmonary patients with substance abuse is necessary via a team cooperation among psychiatrics, psychologists and an internal physician in hospitals because medical treatment alone is not sufficient in such cases.