This essay analyses the later fiction of Nobel Prize-winning writer Isaac Bashevis Singer through the prism of his vegetarianism. Singer figured his adoption of a vegetarian diet in 1962 as a kind of conversion, pronouncing it a religion that was central to his being. Here I outline Singer's vegetarian philosophy, and argue that it was the underlying ethical precept in the fiction written after the conversion. I demonstrate the way in which that ethic informs the presentation of both Judaism and women in Singer's later writings. The piece concludes with the suggestion that this vegetarian ethic was the mainspring of the critique of humanism found in Singer's final novels.