This study is a non-interventional, observational study in which Zemplar® Injection is prescribed in the usual manner in accordance with the terms of the local Summary of Product Characteristics (SmPC) with regards to dose, population and indication. The study population consists of participants receiving hemodialysis in whom the diagnosis of secondary hyperparathyroidism has been established, and who are not adequately controlled with the oral VDR activator (calcitriol or alfacalcidol). Participants will be included via consecutive sampling. To be included, participants should have a clinical indication to initiate treatment with Zemplar® Injection due to: (1) a diagnosis of secondary hyperparathyroidism and (2) because they require a change in treatment for secondary hyperparathyroidism (e.g. due to a lack of effectiveness of the previous treatment). Each participant will be observed during his/her Zemplar® Injection treatment regimen for a maximum period of 12 months.