OBJECTIVES Hyperphoshatemia or elevated phosphorus in the blood is prevalent in patients with chronic kidney disease - mineral and bone disorder (CKD-MBD) and independently and significantly contributes to morbidity and mortality. The objective of this study is to perform cost - minimization analysis of the newly available medicines sevelamer carbonate (SC) and lanthanum carbonate (LC), for the treatment of hyperphosphatemia in CKD patients not on dialysis (CKD-ND) in Bulgaria. METHODS The results of the head-to-head clinical trial conducted by Spraque (2009) demonstrated equivalent efficacy and safety profiles between the two treatment options. To differentiate the cost in high dose and low dose therapeutic regimes was performed a cost-minimization analysis. Based on that was forecasted the expected cost savings for four years period. Discounting rate of 3.5% was applied. The robustness of the results was tested through sensitivity analysis (SA) using Tornado diagram. RESULTS The estimated treatment cost per patient/per year with SC and LC was 1441,75€ and 1569,50€ respectively at the low dose regimen (4000 mg of SC vs.2000 mg of LC), while within the high dose regimen (6400 mg of SC vs.3000mg of LC)  it was 2306,80€ and 2354,25€ respectively. Expected cost savings (discounted) for the four years period within the assumed market shares was between 1 348 794€ and 2 696 431€ at the low dose regimen, while at the high dose regimen the estimated cost savings was between 501 593€ and 1 001 532€ respectively. The results of SA (discounted) show that the major cost drivers in the treatment of hyperphosphatemia were  the unit costs of SC and LC. CONCLUSIONS The equal efficacy and lower cost of sevelamer carbonate than lanthanum carbonate when used for treatment of hyperphosphatemia in patients with CKD -ND in Bulgaria should made the sevelamer carbonate a preference alternative.