The influence of two temperatures on the development of Dermacentor marginatus evolutive cycle was studied. Tests performed under controlled laboratory conditions at 21 °C, 80 % RH and 27 °C, RH 80 %, on ten fully engorged female ticks collected from naturally infested goats, in Cluj County, Romania. Hatched larvae were fed on white mice and the nymphs and adults on guinea pigs. The following parameters were evaluated: egg incubation; pre-feeding, feeding and pre-moulting for larvae and nymphs; pre-feeding, feeding, pre-oviposition and oviposition for females. Significant differences (p < 0.001) were observed in: egg incubation period (29.4 ± 1.07 at 21 °C; 5.9 ± 0.73 at 27 °C) and pre-moulting duration of larvae (18.9 ± 1.02 at 21 °C; 6.1 ± 0.58 at 27 °C) and nymphs (21.3 ± 0.87 at 21 °C; 19.9 ± 0.71 at 27 °C). The average duration of the developmental cycle was 133.9 days (range 122-154 days) at 21 °C, and 94.2 days (range 83-111 days) at 27 °C.