EWTN Catholic Q&A
Pope John Paul II's body preparation after death
Question from Dave on 04-16-2005:

Why was the Pope not embalmed?

Answer by Colin B. Donovan, STL on 04-17-2005:

We were not told. It could have been his preference. It could have been that unlike in the United States in other countries they do not generally embalm. We only know the fact: he was not embalmed.