This paper aims to investigate James Joyce`s use of excremental imagery in Ulysses in accordance with his definition of art that "Art is the human disposition of sensible or intelligible matter for an aesthetic end." Toward that goal, the reactions of the book`s three main characters to the excrements and eliminatory activities were examined in order of appearance. Upon examination, Stephen Dedalus was concerned with the theological problems and artistic endeavors of creation as well, while Leopold Bloom focused more on the practical aspects of the excremental act, as well as his domestic suffering, especially that caused by his only son`s early sudden death. Molly Bloom, Bloom`s voluptuous wife, was indulged in planning to satisfy her sexual desire by resolving her husband`s sexual apathy, which had lasted since their son`s loss. As is evidenced in the scrutiny, each figure reveals his or her own characteristic features in terms of structure of consciousness, or pattern of life. Accordingly, it appears that Joyce used the eliminative images as a compositional principle for the characterization of the three principal figures appearing in Ulysses, which is generally regarded as a Trinity from the standpoint of its subject and structure.