During the study of nematode fauna of the order Dorylaimida in Dezful, two new recorded species, Prodorylaimus obesus and Drepanodorylaimus picardi, were identified for the first time from Iran. The genus Prodorylaimus is differentiated from other genera in the family Dorylaimidae by having a body length ranges from 1 to 5 mm, smooth cuticle without longitudinal ridges, lip region mostly slightly offset, guiding ring double, tail elongate to filiform and similar in both sexes, female reproductive system amphidelphic and presence of 13-31 contiguous supplements in males. Prodorylaimus obesus is distinguished from closely related species by its rather small body,1.5–1.8 mm long; odontostyle typical, 22-23 μm long; tail elongate, dorsally curved (ć = 1.9-2.2); vulva transverse, V = 54-57; spicules dorylaimoid, 62-65 μm long and 14-15 contiguous ventromedian supplements in male specimens. The genus Drepanodorylaimus is differentiated from other genera in the family Dorylaimidae by having a body length ranges from 0.9 to 2.3 mm, smooth cuticle without longitudinal ridges, lip region contiuous with body, guiding ring double, odontostyle mostly slightly sinuate, 2.0-2.5 times the labial width long; cardia long and slender; tail attenuated, uniformly tapered, 6 to 26 anal body diameter long; female reproductive system amphidelphic, the uterus never contains spermatozoa and completely absence of males. Drepanodorylaimus picardi is distinguished from closely related species by its medium body size,1.7–1.9 mm long; odontostyle slightly sinuate, 23-24 μm long; vulva longitudinal, sunken in body contour, V = 46 and attenuated tail (ć = 12-14), 265-335 μm long, terminus hooked.