(Z)-9-tricosente (muscalure) was evaluated as an attractant forMusca domesticaL. in the field in paired tests with different types of traps; panels painted with adhesive, flypaper strips, sugar bait in pans, and electric grids. The addition of muscalure (0.5–100 mg/trap) increased the numbers of flies caught by these traps by 3.4, 2.8, 7.0, and 12.4 times, respectively. Several kinds of box traps were ineffective. Muscalure-baited traps caught about equal numbers of males and females in the field in contrast to the lahoratory, where only males were attracted to muscalure in olfactometer studies.