This research had three main goals: to control whether children would show significant improvement in cognitive test scores following piano/keyboard instruction; to compare whether the spatial tasks would show greater improvement than other tasks; and to examine whether the effects of piano/keyboard training on spatial tasks are gender differentiated. Sixty-one kindergarten children received two piano/keyboard lessons weekly during one school year. Six Kaufman Assessment Battery for Children subtests were administered before and after the instruction period. Following piano/keyboard instruction, participants improved significantly in Hand Movements, Gestalt Closure, Triangles, Spatial Memory, and Arithmetic but not in Matrix Analogies. Boys had significantly better gain scores than girls in Triangles. It is hoped that these findings contribute to the growing body of research investigating the extra-musical effects of music instruction.