Light-microscope studies revealed the presence of phasmids in the mid-tail region in species of the genera Tylenchulus, Trophotylenchulus (syn. Trophonema), Sphaeronema and Meloidoderita in Tylenchulidae. Scanning electron microscopy studies on Sphaeronema species verified these observations. Absence of phasmids or phasmid-like structures was confirmed for genera placed in Paratylenchinae and Tylenchocriconematinae in the same family, and for other taxa of Criconematoidea. This first record of phasmids in the superfamily Criconematoidea requires reconsideration of the systematic position of Tylenchulidae and of the relationships of the genera currently placed in this family. Presence of phasmids, deirids and other morphological characters place Tylenchulidae in a basal position in Criconematoidea.