A bowling ball has a heavy core of given density; the core has an asymmetrical shape that affords no planes of symmetry. The core is encompassed by a spherical shell of lower density; the shell may include two layers, a relatively hard outer layer of an acrylated resin or urethane resin and a more resilient, softer inner layer, usually of urethane or filled polyester resin. A balancing weight, to compensate for finger holes to be drilled into the shell, is preferably an integral part of the bowling ball core. The density of the balancing weight is usually greater than the density of the rest of the core.