In the fission yeast Schizosaccharomyces pombe, cytokinesis is thought to be controlled by the daughter spindle-pole body (SPB) through a regulatory pathway named the septation initiation network (SIN). Here, we demonstrate that laser ablation of both, but not a single SPB, results in failure of cytokinesis. Ablation of only the daughter SPB often leads to activation of the SIN on the mother SPB and successful cytokinesis. Thus, either SPB can drive cytokinesis.