B-cell activating factor belonging to the TNF family (BAFF) is important for the survival of autoreactive B-cells in systemic lupus erythematosus (SLE). However, the association between serum BAFF levels and SLE disease activity is controversial. Independently, autoantibodies targeting BAFF [immunoglobulin G (IgG) anti-BAFF] have also been described in SLE patients and were associated with increased disease activity. The aim of our study was to analyse the relationship between SLE disease manifestations and serum levels of BAFF, IgG anti-BAFF and BAFF-IgG complexes.