Background: Sickle cell disease (SCD) is group of hemoglobinopathies associated with hemolytic anemia and vasoocclusive complications. All forms of SCD are inherited in an autosomal recessive fashion. Parathyroid hormone plays an essential role in calcium and phosphorus homeostasis, which is achieved by its action on target organs (intestine, bone and kidney), leading to normal bone formation and mineralization and normal physiological concentration of calcium and phosphorus. Objectives: This study aimed to detect the effect of sickle cell disease on parathyroid hormone and consequently on serum calcium (S.Ca), phosphorus (ph), alkaline phosphatase (alk.Ph) and magnesium (Mg) on patients with sickle cell anemia. Subjects and Methods: Forty children known as sickle cell disease patients, twenty of them were SCD (HbSS) (11 males and 9 females). The other twenty were known SC trait (10 males and 10 females). The ages of the children ranged from 5 to 15 years old. All were in non-crises state in routine Outpatient Clinic visits, compared to twenty apparently healthy, age matched and with normal hemoglobin from Atfal Masr Hospital as control. Neither patients nor control received calcium supplementation before the study. Results: The results indicated that sickle cell patients and sickle cell trait patients had hypocalcaemic tendency associated with supernormal parathyroid hormone level and implied impaired calcium absorption from intestine leading to disturbed calcium metabolism, which might contribute in skeletal changes seen in sickle cell patients. Conclusion: We found that there was statistically significant decrease in serum Ca levels accompanied with increase in serum PTH, ph, alk Ph and Mg levels in SCD and Sickle cell trait patients compared to control group.