Abstract
This article investigates the esse of the res et sacramentum of the eucharist in the thought of Thomas Aquinas, attempting to fill a lacuna in eucharistic theology. It proceeds from the questions on Christ’s esse in the Disputed Question on the Union of the Incarnate Word and the tertia pars of the Summa Theologiae, with a short synthesis arguing that Christ exists by one esse. Then, it argues that the eucharist exists by this same esse by answering two possible objections, taken from the many instances of the eucharist across the globe and Christ’s unique mode of sacramental presence, to the eucharist only having this one esse.