Efficiency, ultrafiltration, internal volume, and erythrocyte loss were studied in four new coil dialyzers. One coil, the 1 sq m polypropylenewrapped cuprophane twin coil proved to offer the most suitable combination of high efficiency, good and predictable ultrafiltration, low internal volume, and very high erythrocyte recovery. In our home hemodialysis program we have demonstrated that even the less ideal 1.45 sq m cellulose coil will give complete patient rehabilitation and that routine blood transfusion is not necessary for maintenance of the hematocrit. With the introduction of 1 sq m cuprophane coil into the home program better and more asymptomatic control of ultrafiltration has been gained, a very important benefit. We are unable to share the opinion that coil dialyzers are synonymous with symptomatic dialysis and high transfusion requirements. Indeed, in our experience, coil dialyzers have proven to be very suitable for longterm home hemodialysis.