This study was undertaken to investigate whether levels of anti-alpha-1, 6-glucan antibodies in human sera correlate with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Serum samples were collected from patients with SLE (n = 30), RA (n = 30) and healthy adult volunteers. IgG, IgA and IgM levels against alpha-1, 6-glucan were measured using enzyme linked immunosorbent assays. Anti-alpha-1, 6-glucan IgG prevalence was raised in patients with active SLE (73.3%) and RA (60%) compared with healthy controls (13.3%). Strong correlation between anti-alpha-1,6-glucan-IgG levels and anti-perinuclear factor (r = 0.642; p < 0.05) in RA patients or anti-nuclear antibodies (r = 0.675; p < 0.05) in SLE patients was observed. No significant differences in anti-alpha-1,6-glucan-IgA or-IgM levels were noted between different groups. We conclude that anti-alpha-1,6-glucan-IgG levels were significantly elevated in patients with SLE or RA and positively correlated with disease activity.