Systemic lupus erythematosus (SLE) is an autoimmune disease which may negatively influence fertility. Treatment with cyclophosphamide can damage the ovaries. The ovarian function can also be reduced by autoimmune oophoritis in lupus patients. We analysed the influence of SLE on the ovarian reserve against disease intensity and duration of illness. We determined the ovarian reserve in 33 premenopausal SLE patients without previous cyclophosphamide-treatment by measuring the anti-Muellerian hormone (AMH) and compared these with the AMH values of 33 age-matched healthy controls. Numbers of children and miscarriages were reported. Disease intensity of the SLE patients was determined using SLEDAI and ECLAM and duration of illness was taken into account. We found that the AMH values in the SLE group were significantly lower than in the healthy control group. No significant differences between the groups regarding number of children and miscarriages were noted and no correlation between the AMH value and the duration of illness or the SLEDAI as an indicator of disease activity was found. Despite mild disease activity SLE patients had a significantly lower ovarian reserve than age-matched healthy women. This could be a sign that SLE itself has a negative influence on the ovarian reserve.