Medicare Home Hemodialysis Improvement Act of 1990 - Amends title XVIII (Medicare) of the Social Security Act to cover the services of a home dialysis aide provided by a renal dialysis facility to persons who are nonambulatory, whose health would be endangered by travel to and from a dialysis facility, who have no other potential caregiver who is available or able to provide home hemodialysis, and who are eligible for ambulance transportation to and from a renal dialysis facility. Sets forth home dialysis payment amounts, but prohibits payment in excess of the Medicare payment which would otherwise have been made for such ambulance services.

Directs the Secretary of Health and Human Services to conduct a study and report to the Congress on the costs and effectiveness of various home dialysis services available to end stage renal disease patients.