The brown dog tick (Rhipicephalus sanguineus), which is thought to be the most common    tick in the world and a carrier of numerous infections to both human and dogs, is currently the subject of debate regarding its taxonomic classification. The objective of this study was to evaluate the differences in biological parameters between the winter and summer and the morphological difference of R. sanguineus reared on different host (dogs and rabbits). Regarding the difference in biological parameters between different stages of ticks recorded in winter and summer, there were significant differences in the preoviposition, oviposition, incubation, hatching periods, longevity of larvae, nymphs and unfed adults in addition to feeding periods of larvae, nymphs and unfed adults.  The total life cycle of ticks in winter took longer time (75±4.58 days) than in summer (61.56±4.79 days). Otherwise, there are some morphological differences recorded in the unfed and fed R. sanguineus reared on dogs versus those reared in rabbits. These differences were significant and noticed in the size of different stages of R. sanguineus tick as the shape of the dorsal tail of spiracular plate is longer in adult male tick reared on dog than those tick reared on rabbits. Also, the eggs were spherical in shape in ticks fed on dog, but were slightly oval in ticks fed on rabbits. In conclusion, there were some variations in the biological parameters of R. sanguineus ticks between different seasons in addition, the morphometric features of ticks were varied according to host.