Significance Mistakes in chromosome attachment activate the spindle assembly checkpoint (SAC) to delay anaphase onset. However, it is poorly understood how this checkpoint is silenced to initiate anaphase once all chromosomes are attached properly. Our research uncovers the SAC silencing network (SSN) in budding yeast. Chromosome bipolar attachment applies tension on chromosomes. The SSN prevents SAC silencing prior to tension generation but triggers SAC silencing once chromosomes are under tension, thereby ensuring that cells enter anaphase only after bipolar attachment. Our data indicate that the coordination of SAC silencing with chromosome attachment is achieved through the modulation of the phosphorylation of a kinetochore protein.