Background and objective: Toxoplasma gondii is an important opportunistic parasite in immune-compromised individuals that causes toxoplasmosis. An intracellular pathogen could cause severe complications. Diabetes is a significant component that enhances the host's vulnerability and risk of acquiring a variety of infections. The objectives of the current study are to reveal the relationships between toxoplasmosis and type 2 diabetes in addition to find out the most specific gene for the detection of Toxoplasma gondii. Methods: In this case-control study, 201 blood samples were taken from type 2 diabetic women with 100 healthy women as control groups to detect anti-Toxoplasma IgG and IgM antibodies by performing latex agglutination test and Enzyme-Linked Immunosorbent Assay (ELISA). Detection of B1 and RE genes of Toxoplasma gondii among seropositive individuals by nested PCR and evaluation of leptin hormone in both groups were performed. Results: Among 201 type 2 diabetic cases, 64 cases (32.0%) were seropositive for anti-Toxoplasma antibodies, with 15 samples (15%) among 100 healthy control group via latex agglutination test. ELISA performed for only latex positive samples and the results were 64 ((32%) IgG+, (0%) IgM+) patient group (15.0% IgG+, 0.0% IgM+) healthy group with the P-value 0.0001 which is highly significant. The results of nested PCR were (46.88%) (IgG+, IgM-) and (1.56%) (IgG+, IgM-) for B1 and RE genes, respectively. Increased levels of leptin hormone were observed in patients in compare to healthy controls. Conclusion: Both Diabetes and the elderly increase the chance of vulnerability to get toxoplasmosis. Diabetes, toxoplasmosis and high body mass index results in elevation of leptin hormone that leads to diabetes. B1 gene is the specific gene for detection of T. gondii in our area.