Abstract: Autism is a pervasive neurodevelopmental disorder that appears in the first 3 years of life. Causes of autism have not yet been recognized and for unknown reason the brain's normal development of social and communication skills is affected. In view of the fact that some individuals might show only slight disturbances in behavior or mild developmental delays, professional diagnosis is difficult. Since, blood is a major factor in the welfare of individuals, the objective of the study is to assess features of blood of autistic children. Blood samples were obtained from the fingers of autistic children and their mothers. For light microscopy, blood specimens smeared thinly on glass slides, dried, fixed and stained with Leishman’s. For electron microscopic examination blood buffy coat was fixed with 4F1G and ultrathin sections were double stained with uranyl acetate and Lead citrate. Light micrographs of autistic child’s peripheral blood showed remarkable erythrocytes morphological alterations. Blood of autistic mothers showed alterations analogous to those observed in their children but less frequent. Ultra structurally, nuclear changes including, nuclear pocket type I, membrane blebbing as well as, absence of mitochondria was noticed in most leukocytes. Platelets alterations were also detected. It could be concluded that autism is associated with comparable alterations in blood cells in autistic candidates and their mothers. The erythrocyte alterations collectively, indicated decreased oxygen capacity of erythrocytes in blood circulation including, circulation in epitomes of fetal brain. Sub cellular alterations in leukocytes especially lymphocytes and plasma cells resulted in their malfunctions.