Submitted in fulfillment of the Master of Technology : Biomedical and Clinical Technology, Durban University of Technology, 2014. / INTRODUCTION End stage renal disease (ESRD) occurs once 90 % of the kidney function is lost. Patients with ESRD must either undergo medical treatments, like haemodialysis, that substitute the function of the kidney, or they must have a kidney transplant. In the 1970s, haemodialysis treatment took 8 to 12 hours, three times per week. As technology advanced, dialyzers were able to handle more dialysate and higher blood flow rates hence treatment times were shortened to between three and five hours per treatment which has remained the norm until present day. One clinic in Tassin, France remained on the longer dialysis program and noticed advantages for patients who were on extended dialysis times. One of the major problems with dialysis done in the traditional sense is that it tries to provide a lot of therapy in a short period of time, and it is difficult to clear toxins and fluid in that time, Nocturnal dialysis provides a greater amount of toxin removal over a long period of time. AIMS AND OBJECTIVES The main aim of this study was to determine if nocturnal dialysis resulted in improved dialysis clearance, better overall patient health and a better quality of life. The primary objective of this study was to compare the clearance of small molecules (for example, urea, phosphate, creatinine and potassium) and large retention products (for example Parathyroid Hormone (PTH) and 2-Microglobulin) between the two haemodialysis procedures. The secondary objective was to compare the quality of life and survival of patients on both nocturnal and daytime dialysis. METHODOLOGY Thirty patients with End Stage Renal Disease (ESRD) presenting to the Sunninghill Hospital Dialysis Unit for treatment, who met the inclusion criteria, were recruited to participate in this study. Blood samples were taken for each participant at a baseline, 3 month and 6 month interval. The Kidney Disease Quality of Life Survey Questionnaire (KDQOL: SF- 36TM) was also given to each participant to complete. This survey consisted of three parts: 1) Physical Component Summary 2) Mental Component Summary and 3) Burden of Kidney Disease. This survey helped to predict the quality of life of the patients in each group. RESULTS In this study, non-significant effects of treatment were found for all small solutes individually. This study showed that there was a statistically significant increase in both dialysis adequacy and the clearance of large molecules (Parathyroid Hormone and Beta-2-Microglobulin) in the nocturnal haemodialysis group. The results of the KDQOL: SF-36 survey showed that the nocturnal dialysis patients scored higher in both the Physical Component Summary and the Mental Component Summary which means that they felt they were in better physical and mental health. The survey also showed that the nocturnal dialysis patients felt the burden of kidney disease less than those patients dialyzing during the day. CONCLUSION Firstly, dialysis adequacy as defined by the formula Kt/V, increased in the nocturnal group while it levelled off in the diurnal group. Secondly, both the Parathyroid Hormone levels and Beta-2-Microglobulin levels decreased more in the nocturnal group therefore resulting in statistically significant effects of treatment. The third and final conclusion drawn was that nocturnal haemodialysis resulted in better physical health, better mental health and a lower burden of kidney disease was felt by patients undergoing nocturnal haemodialysis.