To evaluate monthly percentage changes of intact parathyroid hormone (iPTH) and other major bone marker levels in patients with secondary hyperparathyroidism (SHPT) undergoing hemodialysis (HD) and receiving paricalcitol. A total of 493 (F/M 244/249) adult patients with SHPT who were undergoing HD in 22 HD units and receiving paricalcitol treatment, with iPTH > 300mg/mL, adjusted serum levels of calcium (Ca) < 10.2mg/dL, and serum levels of inorganic phosphorus (iP) < 6mg/dL were included in this multi-center, national, prospective, observational study. Data regarding efficacy, safety, and adverse events of paricalcitol treatment were collected during a 12-month follow-up period through monthly visits along with serum iPTH, Ca, iP, alkaline phosphatase (ALP) and other required biochemistry tests as necessary. Mortality data until 6months after the end of the study were also investigated. The mean age was 58.3 ± 15.8years and the mean duration of HD was 6.2 ± 5.5years, respectively. As of 12th month, mean iPTH values decreased from 646 ± 424pg/mL to 473 ± 387pg/mL (p < 0.001); no statistically significant changes were observed in Ca levels (p > 0.05). Serum ALP levels also significantly decreased (p = 0.001) and serum phosphorus levels significantly increased (p < 0.001) during the study observation period. Reasons for early terminations were being lost to follow-up (n = 119, 24.1%), hyperphosphatemia (iP > 6mg/dL, n = 108, 21.9%), low iPTH levels (iPTH < 150mg/dL, n = 97, 19.7%), and withdrawal of consent (n = 41, 8.3%). In total 32 patients (6.5%) were prematurely terminated the study with hypercalcemia (Ca > 10.2mg/dL). 46.9% of those hypercalcemic patients had other anomalies with iP and iPTH levels along with hypercalcemia. Paricalcitol treatment, resulted in successful iPTH control. In approximately 6.5% of the patients paricalcitol treatment was discontinued since Ca levels reached > 10.2mg/dL in those patients. No unfavorable effects on serum phosphorus and Ca-phosphorus (Ca × P) product were observed.