The aim of this study was to assess the value of analysis of pulmonary venous flow in the evaluation of the haemodynamic status of patients with chronic renal failure with normal left ventricular function, treated by haemodialysis. Pulmonary venous flow was recorded immediately before and after haemodialysis in 27 patients with chronic renal failure and a mean age of 44 years. Three groups of patients were defined according to the change in mitral E/A ratio: Group I (E/A < 1 before and after dialysis), Group II (E/A > 1 before and < 1 after dialysis) and Group III (E/A > 1 before and after dialysis). There was a significant difference between these subgroups before dialysis with respect to age, S, D, VTI S, Total VTI, VTI S/Total (p < 0.05). However, because the values overlapped, only a VTI S/Total ratio greater than 59% differentiated patients in Group II from those in group III (p < 0.05). After dialysis, the change in S/D and VTI S/Total ratios increased in Groups I and II and decreased in Group III. The authors concluded that 63% of patients without LV dysfunction on haemodialysis have abnormalities of relaxation which are latent in 47% of cases due to increased filling pressures diagnosed by a VTI S/Total ratio > 59% or simply because the patients are over 50 year old.