In order to demonstrate systematic spatial variations of cancer morbidity in the French "department of la Manche" (1979-1981), heterogeneity and spatial autocorrelation tests are performed. The "canton" (electoral ward of around 10,000 inhabitants) is retained as the statistical unit and the standardized incidence ratio (SIR) in each ward for the most frequent cancer sites, as morbidity rate. For males, three cancers show organized patterns: upper respiratory and digestive tract cancers with a North/South gradient; lung and other respiratory cancers mainly in the urban wards; and cancer of the skin with a high incidence on the West coast and a low incidence in the northern area. For females, cancer of the skin is the only one to show significant spatial variation characterized by a pronounced South/North gradient. The possible etiological factors involved are discussed for each cancer site.