The objective of this study was to assess relationship between smoking, some other risk factors and ulcers development in intensive care unit. This prospective cohort study was performed in two university-affiliated hospitals. The sample consisted of adult male patients who were admitted to medical–surgical intensive care units. All eligible patients were grouped according to their cigarette smoking status as smoker and non-smoker. The final sample included 160 smokers and 192 non-smokers. Pressure ulcer occurred in 62 smoker patients and 28 of non-smoker who showed significant difference. Also number of pack-year of cigarettes smoking showed significant association with ulcer development. Ulcer stage was significantly different between the two groups. Besides of smoking, age, length of stay, faecal incontinency, diabetes mellitus, anaemia and trauma were significantly associated with pressure ulcers. Our study showed significant association between smoking and development of pressure ulcers.