An adjustable kettlebell includes a carrier having two or more compartments for selectively receiving weight members, a handle attached to the carrier for carrying the carrier, and a retaining device rotatably attached to the carrier for selectively opening the opening of the carrier and for allowing the weight members to be engaged into the carrier, and for selectively closing the opening of the carrier in order to selectively retain either or all of the weight members to the carrier. The weight members may be easily and quickly and changeably attached to the compartments of the carrier without disassembling the carrier.