Systemic autoimmune disorders constitute a well-characterized and separate group of diseases in the field of clinical immunology and rheumatology. Despite their shared characteristics, these diseases have several distinctive features. The similarity and the difference are manifested both in etiology (i.e. the importance and ratio of genetic and environmental factors), in pathomechanism (i.e. the dominance of cellular or humoral immune response), in the disease outcome (fluctuating or chronic progressive) and in the diversity of clinical manifestations (i.e. multiple organ involvements or some dominant target organs/tissues). In the present work the authors describe the features of four prototypic autoimmune disorders - systemic lupus erythematosus, Sjogren's disease, dermato-polymyositis and systemic sclerosis - and characterise in general the common and particular specific points of systemic autoimmune disorders focusing on the variability and subgroups which can be observed even within certain diseases.