Background and Objectives: We aimed at evaluating the efficacy of fine needle aspiration biopsy (FNA) in comparison with histopathology and demonstrating whether cytological study could be a proper diagnostic tool in orbital mass lesions. Materials and Methods: In a cross sectional study during 36 months, patients referred to our ophthalmologic center affiliated to Tehran University of Medical Sciences, for evaluation of orbital masses, were selected for FNA. After the surgery, the results of FNA were compared against histopathologic diagnoses as our gold standard method. Finally, the frequencies of specimen adequacy, the accuracy of FNA in distinguishing benign and malignant lesions and in the exact definitive diagnosis of the disorders were reported. Results: In 27.4% of the total 62 cases, the specimens were inadequate for cytologic evaluations. The rate of specimen adequacy in malignant and benign lesions was 82.6 % and 66.66%, respectively. From the morphologic point of view, the rate of the exact definitive diagnosis of malignant and benign disorders in the total 62 cases was 78.2% and 38.46% and; in the adequate specimens, it was 94.73% and 57.69%, respectively. There was no false positive FNA result for malignant cells and only in one malignant case, the FNA report was falsely negative. All data wee analyzed by SPSS software and p value Conclusion: FNA was considered more beneficial in the diagnosis of malignant lesions. FNA is a relatively noninvasive, rapid, specific, and accurate method for the preoperative primary diagnosis of orbital mass lesions and especially in malignant lesions and in some conditions, specific diagnoses can be achieved.