Background: several studies have found an increase in bone loss and risk of fracture in patients with systemic lupus erythematosus. Objectives: To determine the frequency of low bone mineral density and osteoporosis in a cohort of Egyptian patients with systemic lupus erythematosus and their relation to disease activity. Patients and Methods: This is a cross sectional study which was carried out on 60 patients fulfilling SLICC classification criteria for systemic lupus erythematous.  All patients were attending the Rheumatology Outpatient Clinic and Internal Medicine and Rheumatology Inpatient Department at Ain Shams University Hospital from April (2016) to august (2016). Results: Mean values of lumbar spine, femoral neck BMD were 1.0 ± 0.15   and 0.9 ± 0.15 g/cm2, respectively, with mean T-score values at each site of -1.4 ± 1.3 and -0.8 ± 1.0, the frequency of osteopenia among the studied 60 SLE patients was 40.0% and the frequency of osteoporosis was 25.0%. Conclusion: We found that there is increased frequency of low bone mineral density and osteoporosis among SLE patients.