Primary hyperparathyroidism (PHP) is the most common cause of hypercalcemia. Patients with systemic lupus erythematosus (SLE) can develop hypercalcemia but it is exceptionally due to PHP. There are only few cases of concurrent SLE and primary hyperparathyroidism (PHP) described in the literature. We report a case of a 31-year-old patient having SLE with lupus nephritis class III and anti-phospholipid syndrome, complicated by pulmonary embolism associated to primary hyperparathyroidism causing severe hypercalcemia and osteoporosis. Even if there is no evidence for potential pathogenic association between PHP and SLE, the recognition of this association is very important because of therapeutic and prognostic impact. Early detection of PHP leads to avoid severe complications and significant morbidity.