The aim of this book was to assess the adequacy of haemodialysis in chronic patients undergoing treatment at a private clinic in the midwest of Santa Catarina. This is a cross-sectional, qualitative study. The study comprised 29 patients undergoing haemodialysis through an arteriovenous fistula. Blood samples were collected and sent to the laboratory for urea testing. It was observed that most of the samples showed recirculation rates, either intermediate or high, while the changes observed in the Urea Reduction Rate (URR) and the Kt/V equation were less significant. Gender and age did not significantly affect the increase in the levels of the changes found in the recirculation parameter. It was concluded that, in general, the treatment is being efficient and adequate and that the dialysis adequacy parameters once again proved to be important tools, since they were able to detect the efficiency and/or inefficiency of the dialysis procedure.