Ambiguous figures are visual stimuli that may be perceived in multistable interpretations. The role of attention in modulating perceptual reversals of ambiguous stimuli is not clear. We tested whether perceptual reversals depend on working memory by manipulating its load while the participants were viewing the Necker cube. Increasing working memory load delayed the latency and decreased the frequency of reversals. These effects followed a linear function of load. The findings imply shared resources of the mechanisms responsible for perceptual reversals and working memory maintenance. However, reversals were not completely abolished even with the hard seven-consonants load, suggesting that bottom-up processes continue to operate in the bistable perception dynamics when top-down mechanisms are attenuated.