Abstract: Out of 360 female buffaloes, examined in Lower Egypt during a period of two years (2004-2006), 171 (47.5%) were suffering from reproductive disorders and 216 (60.0%) were infected with internal parasites. The main recorded reproductive disorders were ovarian inactivity (27.5%), endometritis (8.6%), delayed puberty (8.3%), mastitis (5.8%), retained placenta (2.2%), repeat breeding (1.1%) and abortions (1.1%). The main recorded parasitic infections were coccidiosis (42.5%), ascariasis (20.8%), trichostrongylosis (6.9%) and fasciolosis (4.7%). Prevalence of antibodies to Infectious Bovine Rhinotracheitis (IBR) in sera using indirect Enzyme Linked Immunosorbent Assay (ELISA) revealed 43.3%, meanwhile, detection of Bovine Viral Diarrhoea Virus (BVDV) in blood of the examined buffaloes revealed 12.2% using direct-ELISA. Detection of antibodies against IBR in milk samples using milk-ELISA gave good diagnostic potency (31.4%) compared with serum-ELISA (43.3%). Prevalence of IBR and BVD was extremely high in buffaloes with reproductive disorders (78.2 and 72.7%, respectively) or parasitic infections (88.5 and 84.1%, respectively) compared with those without reproductive disorders (21.8 and 27.3%, respectively) or parasitic infections (11.5 and 15.9%, respectively). The difference was statistically significant and indicated a tight connection between infections with IBR and BVD viruses on one hand and occurrence of reproductive disorders or parasitic infections on the other hand.