We consider the problem of testing the roundness of a manufactured ball, using the finger probing model of Cole and Yap [4]. When the center of the object is known, a procedure requiring O(n 2) probes and O(n 2) computation time is described. (Here n = |1/q|, where q is the quality of the object.) When the center of the object is not known, the procedure requires O(n 2) probes andO(n 4) computation time. We also give lower bounds that show that the number of probes used by these procedures is optimal.