Little is known regarding the association of primary antiphospholipid syndrome APLS and proliferative glomerulonephritis GN. We describe a biopsy-documented case with primary APLS and proliferative GN with no evidence of thrombotic microangiopathy TMA, and in the absence of other manifestations of systemic lupus erythematosus SLE. She presented initially with left popliteal deep venous thrombosis and nephrotic syndrome. Her first pregnancy at the age of 26 years resulted in intra-uterine fetal death at term. Two subsequent pregnancies ended up with miscarriages at 3 and 4 months of gestation. Urinalysis revealed glomerular red blood cells of 1.0000.000/ml and granular cast; proteinuria of 13.4 grams/24 hours, which was non-selective; hemoglobin 12 gm/dl, normal white blood cell and platelets; serum albumin 2.6 gm/dl; anti-nuclear antibody ANA and anti DNA were negative and complement levels normal. Lupus anticoagulant was positive leading to a diagnosis of primary APLS. The biopsy findings were consistent with membranoproliferative GN. She continued to have steroid-resistant proteinuria, but stable renal function after a 12-year follow up period. She had 2 pregnancies during this period and was delivered at term using caesarian section. She received heparin during the pregnancies. Later she developed hypertension easily controlled by atenolol. This case provides evidence that primary APLS can be associated with proliferative GN due to immune deposits and not only TMA as previously reported, and in the complete absence of SLE. Performing more renal biopsies in this group of patients may disclose a greater prevalence of proliferative GN and may help in devising a rationale for treatment.