OBJECTIVES: To evaluate the impact on costs of treating complications derived from chronic kidney disease (CKD) in patients undergoing hemodialysis in the private health care system in Brazil. METHODS: Owing to the lack of local databases, a survey with experts was conducted to collect data about the main causes of hospital admissions which resulted from complications during the dialysis period of CKD patients. A universe of 600 patients from reference centers in Brazil was studied. Later, the experts answered to a questionnaire about the procedures needed to manage complications. Then, a micro-costing was performed, only direct costs were considered: length of staying, medical procedures, physician fees and drugs.  Sources used for costing were: CBHPM 2009 v.5 (physicians fees list), Revista Kairos (January 2009) (drugs price list) and Guia Farmacêutico Brasíndice (January 2009) (materials price list). The time horizon of this analysis was 1 year, thus no discount rate was assumed. The perspective assumed was that of the private payer. RESULTS: The 3 most frequent causes of hospital admissions and their respective costs in the studied centers were: cardiac complications (33.27%; R$3799); infections (31.90%; R$3508); and venous access complications (9.20%; R$2268). For an average patient, the total costs in 1 year of treatment were estimated to be R$5393. CONCLUSIONS: This study suggests that for the 600 patients studied group the economic impact for the private payer with hospital admissions caused by CKD complications is significant being as high as R$3236,393 in one year.