Heat ham as directed on label or at 325℉ (160℃) 1½ hours.
Remove from oven and score, cutting diagonal lines ½-inch deep and 1-inch apart.
Cut across lines to form diamond shapes.
Combine jelly, mustard and horseradish.
Spoon mixture, small amounts at a time, at intervals, over ham throughout remainder of baking.
Increase temperature to 425 degrees F and bake until ham is browned and glazed, about 30 to 45 minutes.
(C) 1992 The Los Angeles Times