Objectives: The purpose of this bachelor's thesis is to describe the method of serological diagnosis of Toxoplasma gondii infection at the Teaching Institute for Public health of Split-Dalmatia County. Materials and methods: In the process of serological diagnosis of the parasite Toxoplasma gondii, the Teaching Institute for Public health of Split-Dalmatia County includes a blood sample from which serum is separated for testing by centrifugation, equipment with reagents and the Abbot Alinity analyzer. IgG and IgM antibodies are tested from the serum, where IgM antibodies are a sign of acute infection, and IgG of past. The antibody analysis method is CMIA, which stands for chemiluminescent microparticle method. Samples and reagents have their own carriers and the machine pipettes them, thus realizing the reaction. The reaction signal is light, numerically displayed on the screen in agreed units. Results: Serological examination of the patient's sample revealed the presence of IgG antibodies and the absence of IgM antibodies, which indicates a past toxoplasma infection