The distribution and ecology of centipedes in Norrland (the northern part of Sweden) are investigated. The material comprises about 1200 samples from 926 different localities, most of it collected in a special faunistic and ecological survey. Some problems in the analysis of the material of this survey are pointed out. In Norrland ten species are found outdoors and another seven species occur indoors in the area. The geographical distribution and the constancy for different habitat factors for the seven common outdoor species are shown.