Sarcocystosis is an intracellular immunosuppressant parasitic disease caused by the genus Sarcocystis that infect various animal species and human. The current study was aimed to evaluate cellular and humoral immune responses of experimentally immunized rabbits to whole crude antigen isolated from S. gigantea of sheep. The haematological examination of immunized rabbits showed significant increase in the total number of white blood cells (18.8±2.0 x10³/ µl) and differential leukocyte count including; neutrophils, eosinophils and basophils in comparison to non-immunized group. By evaluation of phagocytic activity, the number of phagocytes engulfing the pathogen was significantly increased in immunized rabbits (22.41±1.8) compared to control group (1.22±0.56). In delay type hypersensitivity of cutaneous reaction, the skin fold thickness approached its maximum (5.70 ±0.11 mm) after 48 hours of intradermal injection of the antigen. The total serum albumin and globulin levels were higher in post-immunized group (6.40±0.25 g/dl and 4.36±0.10 g/dl) when compared to control animals (4.82±0.14 g/dl and 2.04±0.11 g/dl), respectively. By biochemical analysis using both glutaraldehyde reaction test and sodium sulphite precipitation test, immunoglobulin level were higher in immunized animals compared to non-immunized animals. During serological analysis, significant difference (P<0.05) was observed in IgG level in immunized rabbits in comparison to control group. Histopathological examination of immunized rabbits showed increased infiltration with inflammatory cells, congestion, oedema and haemorrhage in different organs. In conclusion, the isolated whole crude antigen of S. gigantea has provided a fundamental insight about immune stimulation for activation of cellular and humoral antibodies in experimentally immunized rabbits. It's crucial to explore cross-reactivity between Sarcocystis and Toxoplasma infections during diagnosis and develop a sensitive test to differentiate and detect potential cross-reactions.