BACKGROUND: Dialysis adequacy, assessed by urea kinetics, is an important determinant of patient outcome, and is therefore an important clinical performance indicator. In this perspective, renal registry data may be useful to compare practices across countries. To serve that purpose available data should be comparable and preferably collected using a standardized procedure. The aim of this study, initiated by the European Renal Association-European Dialysis and Transplantation Association (ERA-EDTA) QUality European STudies (QUEST) initiative, was to make an inventory of the different methods used to determine urea kinetic measurements in the light of the European Best Practice Guidelines. METHODS: Via their national and regional registries, European haemodialysis centres were invited to complete a questionnaire regarding their practice of measuring dialysis adequacy. RESULTS: Fourteen regional or national registries among 51 sent back 255 questionnaires. Great variability in the methodology to assess Kt/V was observed. The urea reduction ratio (URR) was used alone by 37% (in association 46%) of dialysis centres, spKt/V by 25% (35%) and on-line clearance by 4% (12%), whereas only 10% (13%) used eKt/V, as recommended by EBPG. Forty percent of centres measured urea removal less than once a month, 6% of which never measured urea removal and 9% only every 6 months or less frequently. CONCLUSION: Despite the fact that the use of URR is not recommended by EBPG, it was the most commonly used indicator to measure urea removal, whereas eKt/V was only used by a small minority of centres. This study allowed us to point out the need to standardize definitions and procedures and to develop an effective plan for implementation of the guidelines.