Multivariate statistical analyses of six quantitative characteristics revealed conspicuous variation within heteromorphic males of Dermatophagoides farinae (Acari, Pyroglyphidae) collected from house dust samples and from laboratory populations. Cluster analysis, principal coordinate analysis, analysis of variance and discriminant analysis revealed the presence of three heteromorphic forms and proved the taxonomic usefulness of quantitative characteristics such as length and width of idiosoma, length of gnathosoma, width of femur I and length of sternum.