Lymphangiomas are hamartomas which often occur during childhood. Their classification is primarily size dependent and predicts their clinical course. Larger lesions can be life threatening, but for many patients with lymphangiomas, cosmetic disfigurement is the primary concern. Treatment options are limited and have shown only variable success. Repetitive surgical excision may be necessary. We report a cystic lymphangioma of the axilla occurring in association with a Becker's nevus in an infant. Although Becker's nevi have been described in association with other hamartomas, primarily those of smooth muscle, an association with cystic lymphangioma has not been previously reported. We offer a brief discussion of possible developmental mechanisms for their coexistence. In our patient the simultaneous occurrence of a lymphangioma and a Becker's nevus appears to be a localized event, as no other developmental abnormalities are evident.