Longidorus helveticus Lamberti, Kunz, Grunder, Molinari, De Luca, Agostinelli & Radicci, 2001 was for the first time observed in the territory of Slovakia in the soil of Fraxineto-Quercetum forest of riverine plain along the Morava River in south-western part of the country. The characteristic of the species are as follows: body length of 7 mm, odontostyle of 140 µm, rounded head with non-separated lip region, non-bilobed amphidial pouches, vulva slightly behind midbody, tail in females and males rounded, spicules in males about 100 µm long and the first juvenile stage is characterised by digitate tail with a long mucro. The morphometric of females, males and four juvenile stages from Slovak specimens and differential diagnosis from similar longidorid species L. carpathicus, L. picenus and L. silvae from Slovakia as well as from L. profundorum occurring in mixed population with L. helveticus are discussed here.