Preheat oven to 350 degrees.
Cut the bacon slices in half and then wrap one slice around 1 water chestnut. Put toothpick through the bacon and water chestnut to secure the bacon.
Prepare a foil lined cookie sheet and place the water chestnuts on the pan.
Bake for 25 minutes.
While the bacon wrapped water chestnuts are baking, add the ketchup, brown sugar, and Worcestershire sauce to small sauce pan. Cook on medium heat until brown sugar dissolves, about 5 minutes.
After 25 minutes, take out water chestnuts and cover them with the sauce. Bake again for 25 minutes. Serve warm.