A blood meal is essential for tick reproduction and results in the transmission of various pathogens. Therefore understanding the reproductive processes are essential for tick control. Our research indicates the involvement of two factors, one a peptide and the other likely a steroid, in the regulation of vitellogenesis. Here we present data indicating a role for ecdysteroids, as the second factor, in the regulation of vitellogenesis of O. moubata . Injections and topical treatment with high concentrations of ecdysteroids stimulated an increase in vitellogenin and egg laying. Vg synthesis occurs in both engorged mated and virgin females, but is not activated in virgin females sufficiently for eggs to mature. Ecdysteroid titers appeared to coincide with the various stages of engorged mated females but not increase greatly in engorged virgin females. Ecdysteroid receptor expression was investigated by real time PCR and show similar trends in the mated and virgin females. These results suggest ecdysteroids induce vitellogenin synthesis, egg maturation and oviposition in O. moubata .