The aim of this study is evaluation of the effects of nicotinic acid on hyperphosphatemia, PTH and lipid profile in dialysis patients of Imam Hossein hospital of Shahroud. Hyperphosphatemia is one of the most common metabolic disorders in end-stage renal disease patients that is independent that causes change of PTH. Bone fracture, chronic arthralgia , diffuse itching, fatigue, generalized , anxiety are sever changing of lipid profile of Hyperphosphatemia that affect quality of life. Low dietary intake of phosphate is not enough to control Hyperphosphatemia, PTH and hyperlipidemia and needs extra medication to reduce dietary phosphate absorption. Currently the most common indication for niacin or nicotinic acid is control of hyperlipidemia. The most important side effect of niacin is vasodilation and hot flush, that is due to prostaglandin production and is controllable with aspirin. This clinical trial is a prospective study with case and control group in hemodialysis patients in Shahroud to evaluate effects of niacin on serum phosphorous, PTH and lipid profile. After obtaining informed consent, patients will be randomly classified in two groups. Group I will receive nicotinic acid and group II will receive placebo. Inclusion criteria: Age > 15 &<70 years; sign satisfaction; serum phosphorous: 5-7 mg/dl; PTH level > 550 ug/ml; TG >350mg/ml; LDL>150mg/ml and HDL<25 mg/ml; unchanged treatment protocol; (calcium components and Vit D) during last two weeks; unchanged dialysis protocol. Exclusion criteria: pregnancy; known liver disease; active peptic ulcer; carbamazepine use; drug intolerance and not satisfaction of patients. Nicotinic acid will be started as 200 mg/day, patients will be controlled for nicotinic acid's side effects such as GI problems and thrombocytopenia. Calcium & phosphorous will be checked every 2 weeks and per month 200 mg/day nicotinic acid will be increased to 600 mg/day (200 mg additional per month). If phosphorous is lesser than 3.5 mg/day, nicotinic acid will be reduced to 200 mg/day. Nicotinic acid will continue till 12 weeks. Then control group, placebo was used similar case group( 200 mg/day to 600 mg/day in third months) In addition to calcium and phosphorous, PTH will be checked at 0-4-8 and 12 weeks and lipid profile will be checked at 0 and 12 weeks . During the study, dialysis protocol of patients will remain unchanged and dialysis efficacy will be evaluated by BUN & creatinine before and after hemodialysis. Binding drugs to phosphorous and Vit D will be continued as before.