The beautiful target and spiral patterns exhibited by the Belousov-Zhabotinsky (BZ) reaction in thin films of solution are representative of spatiotemporal behavior in a two-dimensional, planar excitable medium. 14 We report here BZ chemical waves propagating on the two-dimensional surface of a sphere. Single- and double-rotor spiral waves develop on the surface of a single cation exchange bead, loaded with ferroin and bathed in BZ reaction mixture containing no catalyst. In an earlier study, 7 ferroin was loaded on cation exchange resin in order to examine chemical wave behavior in an immobilized-catalyst BZ system. Pattern formation was studied in a 0.5 mm layer of ferroin-loaded resin beads covered with a 1.6 cm layer of reaction mixture containing no catalyst. A transition from regular to irregular patterns was found on increasing the concentration of either Br03 or