The environment contains various microbial agents that have potential of causing diseases. Immunity plays an important role of protecting body from various causative agents by recognizing foreign agent and eliminating them from the body but sometimes these immune system acts against self-antigens. Thus, resulting into auto-immune diseases which affects multiple organs including oral cavity. Knowledge of these diseases is not only important to diagnose the diseases but also helps in treatment. This review was undertaken to highlight the hematological investigations used to assess the autoimmune diseases presented with oral manifestations.