Hypotension during hemodialysis is still an unsolved problem. The treatment of patients with cardiovascular instability is efficaciously carried out with the use of ‘profiled dialysis’ (PD) with computerized modulation of ultrafiltration and conductivity. We tested a new profile model which involves progressive decrease of ultrafiltration associated with variable conductivity (‘bell pattern’). We observed 8 stable long-term patients receiving hemodialysis (4 men and 4 women, mean age 63.5 years) for 4 h three times a week. Before our test, sodium balance had reached a steady state in all patients and remained stable during the entire observation period. The sodium balance was established by means of a simple pattern suggested by Ursino and coworkers. The patients were observed for two periods of 1 month each (protocols A and B). The intradialytic mean arterial pressure was studied, checking every hour of dialysis. Statistical analysis was done by ANOVA for repeated measures. We compared standard dialysis with constant ultrafiltration rate and conductivity (protocol A) with sessions performed involving a progressive decrease of ultrafiltration together with a variable conductivity of –0.2, +0.2, +0.6, +0.6, 0, –0.4, –0.4, and –0.4 mS/s (protocol B). We found a lower incidence of hypotension (p < 0.01) with better cardiovascular stability during and after treatment in ‘profiled dialysis’.