Since the beginning of the 19th century, delusions have been classified mainly by their content or theme. Clinical psychopathological investigation requires additional variables that will allow investigators to describe the structure of delusional experience more accurately. Delusions are multidimensional constructs that may change across the various mental disorders. Several authors have developed rating scales with the aim to measure individual dimensions of delusional structure. In this paper, common rating scales are mentioned and the main characteristics of the Simple Delusional Syndrome Scale (SDSS) are summarized. The SDSS scale consists of 7 items (logical organization, systemization, stability, conviction, influence on the action, extension, and insertion), scored from 1 to 5. Results of the statistical analysis confirm good psychometric characteristics of the scale, Cronbach coefficient alpha=0.8327. The SDSS may contribute to a better understanding and diagnostics of delusional disorders and, using statistical methods, can help quantify the relationship between the delusional syndrome and the primary disease process. The SDSS scale may also be utilized in the assessment of changes occurring in delusional syndromes depending on the therapeutic effect of psychopharmacological drugs.