Sixty-nine unselected SLE patients were studied to evaluate the prevalence of avascular osteonecrosis (AVN) and its relationship with steroid therapy and with anticardiolipin antibodies (aCL). All the patients were under treatment with corticosteroids. AVN occurred in seven occurred in seven of the 69 patients (10.14%) and was not related to corticosteroid intake. Seventeen of the 69 patients were also treated with methylprednisolone pulse therapy (MPPT) and cumulated the highest corticosteroid doses but none of them suffered from AVN. Excluding the 17 MPPT-treated SLE patients, corticosteroid intake was significantly higher in the AVN-SLE patients. Abnormal IgG and/or IgM aCL serum levels were found in two of the seven AVN-SLE patients and in 24 of the 62 non-AVN SLE, without a statistically significant difference. None of the seven AVN-SLE patients showed features of antiphospholipid syndrome. We conclude that in SLE patients a continuous high-dose steroid treatment may be considered a risk factor for AVN. On the contrary, MPPT regimen may reduce this risk. Anticardiolipin antibodies might represent an added factor which could play a role in some patients but not in all.