An add-on weight kit for a selectorized dumbbell comprises a second set of nested weights that are similar in shape and structure to a first set of nested weights originally provided on the dumbbell. The second set of weights has a plurality of overlying rails that will underlie an array of similar rails carried on the first set of nested weights. The kit includes a second handle having vertically spaced openings with the second handle being used in place of a first handle originally provided on the dumbbell. The openings on the second handle are arranged relative to the rails on the second set of weights such that the same connecting pin as used on the dumbbell to couple the first set of weights to the first handle can be used to additionally couple a selected number of the add-on weights to the second handle.