Antinuclear antibodies are a group of autoantibodies which are typical for collagenous diseases. By means of the autoantibody profile different sub-groups of systemic lupus erythematosus (SLE) can be identified. This can serve as a certain prognostic factor of the affection. Patients with a negative antibody profile have fewer clinical and laboratory manifestations of SLE. Profile A (anti-dsDNA and/or anti-Sm has, as compared with patients with a negative antibody profile, more frequent organ manifestations. Patients with profile B (anti-RNP) have a higher frequency of Raynaud's phenomenon. Profile C (anti-Ro, anti-La) is characterized in particular by photosensitivity of the skin and secondary Sjögren's syndrome. Profile D (antibodies against centromeres and/or Scl-70) are found in subjects with SLE with traits of scleroderma. Finally profile E (antibodies against histones) are found in SLE induced by drugs. In the submitted study in 28 patients with SLE autoantibodies anti-dsDNA, anti-DNP, extracted nuclear antibodies (ENA-Sm,Ro,La, histones, Sm/RNP, Scl-70) were evaluated and different subgroups of SLE were assessed. Attention was paid to their common characteristics and the activity of the disease. Associations of clinical activity of the disease expressed by the ECLAM index (European Consensus Lupus Activity Measurement) were tested as well as anti-dsDNA levels and also the association of the disease activity with C3 and C4 constituents of complement, CRP and circulating immunocomplexes in serum. Positivity of the antinuclear factor (ANF) was found in 21 patients, while in 7 subjects who were in clinical and laboratory remission, ANF was negative. A negative antibody profile was recorded in 9 patients, profile A was found in 13, 1 patient had profile B, and 4 patients had profile C. Antibody profile D was not found in the group. When using regression analysis and Pearson s correlation coefficient, correlations were found between anti-dsDNA values and the system ECLAM (r = 0.72, p < 0.01), anti-dsDNA and C3 levels (r = -0.59, p < 0.01), C4 (r = -0.50,, p < 0.01), and between the ECLAM system and C3 (r = -0.60, p 0.01) and C4 (r = -0.52, p < 0.01) and also between C3 and C4 mutually (r = 0.72, p < 0.01). From the submitted investigation ensues that investigation of antinuclear antibody levels in SLE is important not only for assessment of the diagnosis of the disease and its activity but also for assessment of the subgroups of the disease and for prediction of its development. As to other indicators of activity, assessment of the C3 and C4 constituents of complement is still important.