Papanicolaou smear cytology is a simple diagnostic procedure for the evaluation and management of external ocular lesions. A variety of benign and neoplastic lesions are examined for correlation of clinical, cytologic, and histologic impressions. Accurate correlation in 38 of 41 eyes substantiates the reliability of Papanicolaou smear cytology to differentiate benign from neoplastic ocular lesions. Cytology proved useful in the preoperative evaluation of squamous cell carcinoma and related tumors of the conjunctiva, and malignant melanoma of the conjunctiva. Cytology also was valuable in the detection of tumor recurrence in squamous cell carcinoma and carcinoma-in-situ of the conjunctiva, and in Meibomian gland carcinoma of the eyelid. The accessibility of ocular tumors makes them particularly well suited for cytologic examination.