Squamous cell carcinoma of the conjunctiva is a distinct rarity, often arising at the corneoscleral limbus and initially resembling pterygium or chronic keratoconjunctivitis. In this paper we report 4 patients with conjunctival squamous cell carcinoma/carcinoma in situ, which comprise all the cases found in the files of Kuopio University Hospital during 1959-1991. The clinical appearance, diagnosis and treatment of the lesions are described. All biopsies were studied for the presence of Human papillomavirus (HPV) DNA (recently demonstrated in conjunctival squamous cell papillomas, precancer lesions and carcinomas) by using in situ DNA hybridization (ISH) and polymerase chain reaction (PCR). Both techniques failed to demonstrate the DNA of any of the following HPV types: HPV 6, 11, 16 and 18 in any of the lesions. The results are discussed in the light of the recently proposed HPV etiology of these lesions.