Peel pineapple; remove eyes; and core.
Cut into chunks.
Combine water and brown sugar.
Bring to a boil.
Reduce heat and simmer 5 minutes, stirring occasionally.
Add pineapple; simmer in syrup until heated through.
Remove from heat; stir in rum.
Pack hot into hot jars, leaving 1/4-inch head space.
Remove air bubbles.
Process 15 minutes in boiling water bath.