• Screening the prevalence of vitamin D deficiency among Egyptian hemodialysis patients on a single center (Ain Shams University hospital).
• Assessing the effect of the native type of vitamin D (Cholecalciferol) on replenishing its deficiency via extra-renal vitamin D receptors (VDR), among Egyptian hemodialysis patients.
• Assessing the effect of cholecalciferol on vascular calcification among Egyptian hemodialysis patients.
• Assessing the effect of cholecalciferol on Blood pressure, parathyroid hormone.

Inclusion Criteria:

1. Both sexes aged between 18-75 years
2. Patients on HD greater than 3 months at least.
3. Stable clinical condition (no hospitalization in the previous 3 months)
4. Informed consent in accordance with the Declaration of Helsinki.
5. PTH level between 150 - 800 pg/ml.

Exclusion Criteria:

1. Hypersensitivity to cholecalciferol.
2. Participant in an another clinical trial within the past 4 weeks.
3. Judged to be unsuitable as a subject by the attending physician.
4. Pregnant or breastfeeding female