This study evaluated the ingestion of microplastic and artificial cellulose in 103 fishes belonging to 21 reef fish species from the southwestern Atlantic. Nine species ingested particles- seven species both types and two only one kind. Fishes ingested more man-made cellulose fibers than microplastics, and these particles were mainly found in the stomach. Haemulon aurolineatum ingested more microplastic and artificial cellulose particles than other species. Overall, transparent particles were dominant in our data. Polyamide was the commonest particle of microplastic, being associated with cellulose microfibers from washing clothes thought wastewater systems. Household sewage, fishery activity and marine navigation might be main sources of artificial particles for these reef fishes. This work provides a background of microplastic and artificial cellulose contamination. These information are important to understand the anthropogenic impact over a poor-examined marine group, the tropical reef species, as well as guidelines to mitigate plastic pollution on reefs.