Cure rates for 631 periocular basal cell carcinomas treated by Mohs surgery proved to be 98.1% for primary lesions and 93.6% for previously treated lesions. All recurrences of primary lesions post-Mohs surgery were located in the medial canthus. Among lesions previously treated, recurrence rates after Mohs surgery were twice as high for medial canthal lesions as for other periocular basal cell carcinomas, 9.5 and 4.5%, respectively. A threefold increased risk of recurrence was observed for medial canthal lesions (post-Mohs surgery) previously treated by radiation as compared to all other treatment modalities. This high recurrence rate may reflect past practices of treating large medial canthal basal cell carcinomas with radiation rather than by other means. Results of our study indicate that primary basal cell carcinomas in the medial canthus can be treated by microscopically controlled excision with excellent results.