Two new location of Phymatodes pusillus (FABR.) were found in Poland (Gołuchów YT05, Kozienicka Forest EC20). The species is new to the Mazovian Lowland fauna. Description of egg is given, as well as some details of biology, among others host plant of larvae - Quercus petraea (MATTUSCHKA) LIEBL. Previously unknown parasitoids of P. pusillus were bred: Xorides praecatorius (F.), Neoxorides sp. (Ichneumonidae) and Spathius curvicaudus RAT Z. (Braconidae).