We analysed the prevalence of clinical manifestations and immunological parameters in 194 patients with SLE and classified them in subgroups according to age at onset, gender and type of antibodies: we detected significant differences in the various subgroups. In SLE that initiated before the age of 20 years, the most frequent manifestation at onset was malar rash (25% vs 14%). During the course of the disease, this group had a greater prevalence of malar rash (70% vs 45%), mouth ulcers (48% vs 29%), and convulsions or psychosis (35% vs. 17%). In SLE that initiated late in life (after 50 years) malar rash was less frequent at onset and during subsequent evolution of the disease (27% vs 45%). The existence of ANA, and elevated values of anti-dsDNA, anti-ENA and antiphospholipid antibodies also differentiated the SLE subgroups with clinical significance.