Refrigerate 2/3 of the bacon until needed. It is easier to wrap the wieners with cold bacon. Wrap each cocktail wiener with a piece of bacon and secure with a toothpick. Place on a large baking sheet. Sprinkle brown sugar generously over all.
Bake for 40 minutes in the preheated oven, until the sugar is bubbly. To serve, place the wieners in a slow cooker and keep on the low setting.