The Stoke Renal Unit has been at the forefront of peritoneal dialysis (PD) research for much of the past two decades. Central to this work is the PD cohort study, which was started in 1990 and is based on regular outpatient measurements of peritoneal and clinical function, correlating these with long-term outcomes. It has provided a wealth of information on risk factors for morbidity and mortality in patients on PD, the most significant being demonstration of the effects of time and dialysate glucose exposure on changes to the peritoneal membrane, as evidenced by increases in small solute transport. Early on, the study confirmed the adverse relationship between high small-solute transport status and outcome but more recently suggested that this relationship no longer held with modern techniques for managing patients on PD. Central themes of the PD research in Stoke have included evaluation of euvolemia, the importance of ultrafiltration and how best to achieve it, and detailed assessments of transmembrane water movement. The work has included the study of sodium removal and the use of novel low sodium dialysates. More recently, attention has turned to the significance of impaired ultrafiltration capacity in patients on PD as a sign of structural membrane damage. It is hoped that further work in this area will identify preventive strategies.