A new species of Lithobius from a Sardinian cave (Cagliari, Santadi, loc. Su Benatzu, Grotta “Pirosu”, 576 Sa/Ca, m 270) is described. Lithobius nuragicus n. sp. belongs to the subgenus Lithobius s. str. and is related to Lithobius variegatus Leach, 1814, occurring in the British Isles, Brittany, Channel Isles, Iberian Peninsula, Maghreb, Sicily and Southern Italy. This new species is differentiated from L. variegatus by the number of prosternal teeth (3+3), the number and arrangement of ocelli (1+3; little, depigmented, not contiguous to each other, in the center of a depigmented area, posterosuperior ocellus larger than the other ocelli), the size of the organ of Tòmòsvàry (larger), the number of antennal articles (79-86), the number of dorso-lateral and dorso-median setae and the shape and size of the claw of the female gonopods (4-5; 10-11; short, with a small lateral denticle on the internal side).