Background: Precancerous lesions are disorders that are highlylikely to become malignant. Early diagnosis of precancerous skinlesions helps to prevent skin cancers. The aim of this study wasclinicopathological assessment of precancerous skin lesions inpatients referred to the dermatology department of Imam Rezahospital.Method: Two hundred and nine patients who were diagnosed withprecancerous lesions and referred to the dermatology departmentof Imam Reza hospital from 1997 to 2007 were studied. Studyparameters included participants’ age, sex and occupation, typeof precancerous skin lesion, clinicopathological type of the lesionand location. The data was collected from the patients’ recordsin the dermatology department and their microscopic slides inthe pathology department.Result: The most common precancerous skin lesion was actinickeratosis (68.4%) followed by Bowen’s disease (7.2%). About67.5% of the patients were male with a mean age of 61.7 years.Moreover, 53.1% of the patients worked outdoors. The mostcommon site of the lesions was head and neck (83.3%) and 18.7%of lesions were associated with malignancy. The most commonpathological form of actinic keratosis was the proliferative type(28.9%).Conclusion: The results of this study showed that precancerousskin lesions were more prevalent in men aged over 50 years, insun-exposed areas and in occupations practiced outdoors. Inaddition to squamous cell carcinoma, these lesions could alsobe associated with basal cell carcinoma.