The epidemiology of acute renal failure (ARF) has recently displayed an increasing shift of cases from the renal ward to the intensive care unit (ICU). Accordingly, two groups of physicians are now highly involved in the care of ARF patients: nephrologists and intensivists. Renal replacement therapy has also evolved a great deal over the last 20 years with the development and increasing application of continoous renal replacement therapy (CRRT). Several controversies have developed over which approach to patient care is most desirable and which form of renal replacement therapy should be applied in preference within the ICU. There are also controversies on the best clinical practice for CRRT including indications, vascular access, anti-coagulation, membranes and filters, machines and finally, which specialist should be in overall charge of patient care. Taking advantage of two international meetings on renal replacement therapy and critical care nephrology, we collected the answers to a wide-ranging questionnaire distributed among attending practitioners. We now report the responses of 345 physicians from different centres in a wide variety of countries. The questionnaires were accurately prepared and distributed to the delegates of two international meetings carried out in the US and Europe. The questionnaire was divided into several sections concerning demographic and medical information, epidemiology of ARF, practice of CRRT and current opinions about clinical advantages and problems related to CRRT. Out of the 375 collected questionnaires, only 345 were complete and could be utilized for the analysis. The respondents were from different continents with most in Europe and North America. Physicians were mostly nephrologists or intensivists and only few of them had a combined background. The same was true for the field of operation and medical specialty. Epidemiology of ARF highlights the shift towards more complicated cases occurring in a critically ill population. High variability was found in the practice of CRRT, although it seems that the multidisciplinary approach received a wider consensus. Anti-coagulation and arterial vascular access still represent a major concern for the treatment, while new machines and membranes are considered major advances in the field. CRRT are frequently used even in the absence of acute renal failure (52% of the respondents) the prevalent use being for fluid control, congestive heart failure, acute respiratory distress syndrome (ARDS) and sepsis. Our survey describes in detail the problems encountered in the day-to-day practice of CRRT. The analysis outlines the fields in which further knowledge and education are definitely needed. A deeper understanding of the mechanisms and procedures involved in continuous therapies is probably required both from the view of the nurse and the physician. Several issues are still open and will be matter of controversy in the coming years. For this reason, we hope that our survey will provide a stimulus for new studies to seek evidence for different clinical decisions. A wider application of CRRT in the fields of sepsis and multiple organ failure requires further experience and evidence for clinical benefit. In the mean time, several studies will focus on specific aspects such as cytokine removal and physiological response to continuous versus intermittent therapies. We hope that little by little these studies will contribute towards piecing together the overall picture.