Lumpy skin disease (LSD) is an infectious viral disease of cattle caused by LSD virus (LSDV) of the family Poxviridae characterized by skin nodules covering all parts of the body. There are many aspects of LSD remaining unknown, thus immunological, hematological, and biochemical parameters were estimated. During an outbreak of LSD in Sharkia governorate from Egypt, 211 cows aging (2-4 years) were examined clinically for the presence of LSD lesions during the period from July to November 2014. A total of 134 cows from those showed lesions suspected to be LSD. Recorded clinical signs were pyrexia with the development of skin nodules of varying sizes which ranged from a few to several hundred sometimes coalesced together. Enlargements of the peripheral lymph nodes. Intracytoplasmic inclusion bodies were noticed in the histopathological examination. Immunological studies revealed a significant decrease of lymphocyte transformation rate, phagocytic % and killing % which was marked within 2 weeks postinfection. LSD resulted in non-significant in hemogram in 1(st)-2(nd) day post-infection while a macrocytic hypochromic anemia within 10-14(th) days post-infection. Leucopenia and lymphopenia were recorded 1(st)-2(nd) day post-infection while at 10-14(th) showed granulocytic leucocytosis. Biochemical analysis revealed hypoproteinemia, hypoalbuminemia, and hyperglobulinemia especially gamma globulins. There were a significant increase in serum alanine aminotransferase, aspartate aminotransferase activities, creatinine level, blood urea nitrogen and creatine phosphokinase. LSDV infected cows in early stages revealed leucopenia. Immunosuppressive effect was pronounced later. In late stage revealed hemolytic anemia, leucocytosis and increase of serum CK, which could aid in diagnosis. Disturbance in liver and kidney function tests have been occurred.