This article is from the the official alt.spleen FAQ, by Andrew Stellman with numerous contributions by others.
Andrew says: NOTE: PLEASE DO NOT SEND ANY MAIL TO ME REQUESTING MEDICAL ADVICE! I AM NOT A DOCTOR, AND WILL NOT GIVE YOU ANY USEFUL INFORMATION.
Yes! Unless it was removed, you have a spleen. Some people are even born with more than one spleen. The spleen is a wonderful thing, and you should be aware of your own spleen.