Many interspecific commensal foraging interactions involving birds have been documented. We describe an observation of commensal foraging by a fan-tailed warbler (Euthlypis lachrymosa) with a nine-banded armadillo (Dasypus novemcinctus) in Guerrero, southwestern Mexico. Our observation is similar to those reported from El Salvador by (Komar and Hanks, 2002) and indicates this association between fan-tailed warblers and nine-banded armadillos is more widespread than previously reported.