The morphological and genetic diversity of three parasitic wasps—Euaphidius cingulatus (Ruthe), Euaphidius setiger Mackauer, and Remaudierea plocamaphidis Starý—and their relationships with some species from the genus Aphidius Nees are examined in this article. Partial sequences of the mitochondrial cytochrome oxidase subunit I and nuclear 28SD2 genes revealed weak genetic differences between Euaphidius, Remaudierea, and the selected Aphidius species. Analysis of fore wing size and shape using geometric morphometrics showed that species from the genus Euaphidius have a shorter R1 vein and medially wider wings part than in Aphidius. On the basis of molecular analysis and shape of the wing, we redescribe E. cingulatus and E. setiger, including them in the genus Aphidius. Similar results were obtained for the species R. plocamaphidis, which is also included in the genus Aphidius. In addition to this, we propose to group both E. cingulatus and R. plocamaphidis in the subgenus Euaphidius within the genus Aphidius.