Abstract: Immunity against chicken coccidiosis by in ovo vaccination of Eimeria necatrix in diffevent invasive stages was investigated. The fertile Lingnanhuang broiler eggs were injected through amniotic sac on day 15, 17 and 19 of incubation with oocysts, sporocysts or sporozoites of E.necatrix, respectively. Vaccination doses were in the range of 3×10³~1×10⁴ oocysts, 4×10³~4×10⁴ sporocysts, or 8×10³~8×10⁴ sporozoites per egg. Hatching rates were generally unaffected by vaccination. The hatched chicks were reared in wire-cages and shed oocysts during day 2~7 posthatch for chickens vaccinated with sporozoites and at 7 d posthatch for chicks injected using oocysts or sporocysts. At 17 d, the vaccinated chickens were challenged with 1.2×10⁵ sporolated oocysts of E.necatrix. The immunity against E.necatrix by in ovo vaccination were evaluated through relative weight gain(RWG), reduction of lesion score(RSL), and relative oocyst production(ROP). The chickens vaccinated in ovo with parasite stages had significantly reduced oocysts output(ROPs were in range of 28.1%~60.2%) and lesion score(ranged in 50%~74.9%), and with significant increase in RWG(reached to 73.2%~90.5%) compared to their nonimmunized counterparts. These results implies that vaccination in ovo of E.necatrix invasive stages could induce sufficient immunity against the homologous challenge.