This study aimed to investigate the complementary association between Bovine Viral Diarrhea Virus (BVDV) and Neospora caninum (NC) in the induction of abortion in cattle. The study was carried out on 116 serum samples collected from 116 aborted cows in different Egyptian localities. All blood samples were immediately transported to the diagnostic laboratory. Serum was harvested after centrifugation at 1500×g for 10 min. All sera were divided equally into two microtubes and stored at -20 °C until laboratory testing. Double antibody sandwich immunoenzymatic assay (DS.ELISA) is used for bovine viral diarrhea virus (BVDV) p80/p125 antigen detection and Anti-Neospora caninum (NC) antibodies were detected using an indirect ELISA. Our results cleared that the incidences of BVDV and NC among examined cow's serum samples were 66 (56.9 %), where the incidences of BVDV and NC were 31 (26.72 %) and 35 (30.17 %), respectively. There were 18 (27.3 %) samples that showed mixed infection BVDV and NC incidences among examined cattle serum samples. The study concluded that the prevalence of BVDV and NC are high and widely spread in cattle farms in Egypt. There is a pronounced association between BVDV and NC and concurrent infection in cattle farms in Egypt. So we should coordinate surveillance and control programs on abortifacient pathogens (BVDV and NC) should be developed and implemented, which would reduce the losses associated with these diseases in cattle farms.