Five new and two known species of dorylaim nematodes belonging to the family Dorylaimidae are described and illustrated from Costa Rica. Prodorylaimus paraobesus sp. n. has 1.5-1.9 mm long body; lip region offset by a depression; 35-38μm long odontostyle with thick walls; 'double' guiding ring; transverse vulva and elongate-conoid, dorsally bent tail. Laimydorus esquiveli sp. n. has 1.6-2.1 mm long body; lip region offset by slight depression; 30-32μ m long odontostyle; 'double' guiding ring; longitudinal vulva; males with 12 ventromedian supplements and prerectum terminating within the range of supplements. Laimydorus tropicus sp. n. has 1.5-1.9 mm long body; lip region truncate, offset by depression; 'double' guiding ring; transverse vulva; female tail 14-15 anal body diam. long; male with ten ventromedian supplements and prerectum terminating within the range of supplements. Calcaridorylaimus andrassyi sp. n. has 1.7-1.8 mm long body; slightly offset lip region; 15μm long odontostyle; pore-like vulva and spicules with triple contour and much shorter ventral arm. Coomansinema brevicauda sp. n. has 1.3-1.6 mm long, robust body; 21-22μ m long odontostyle; transverse vulva; short conoid female tail with an elongate dorsally bent projection and male with ten ventromedian supplements. Mesodorylaimus guarani Andrássy, 1968 and Sicaguttur hooperi Carbonell & Coomans, 1986 are reported for the first time from Costa Rica.