Even among the Orthodox community, there are mixed opinions about organ donation. Some say it is acceptable, while others don't see it that way. The reason being that when "Hashem lifts the dead from their graves, there should be a complete body."

In modern times, with organ donations becoming a widely accepted practice, it has become, for the most part, generally acceptable within the broadest terms of Judaism...especially if in making the donation, it saves or betters a living person.

Shalom,
Rabbi Dan