This paper presents the karyotype and external morphology of larva, pupa and adult male of Stictochironomns sticticus (Fabricius, 1781) from Poland. The species of the genus Stictochironomus are generally identified on the basis of pupal and adult morphology. However, the species described in this paper has species-specific markers in the salivary gland chromosomes which allow identification at the larval stage. Karyological markers are evaluated for the Polish population in comparison with other European populations and Stictochironomus species.