The present investigation aims to evaluate the efficacy of six ammonium compounds (tri-ammonium phosphate, ammonium carbonate, ammonium acetate, ammonium chloride, ammonium thiocyanate and ammonium dihydrogen phosphate) as lures for the adults of zizyphus fruit fly, Carpomya incompleta (Beeker) in Christ's thorn orchards under field conditions of Qassim area, Saudi Arabia. Each ammonium compound was tested by using five concentration (1, 2, 3, 4 and 5%). Trap tests indicated that C. incompleta adults showed different degrees of preference for the different tested ammonium compounds. However, tri-ammonium phosphate attracted the highest numbers of C. incompleta. While, all concentrations of ammonium dihydrogen phosphate did not attract any females or males of C. incompleta. Tri-ammonium phosphate and ammonium chloride exhibited their highest attractant at 5% concentration; however, mean CTDs were 6.30 and 0.47 adults. While, ammonium carbonate, ammonium acetate and ammonium thiocyanate exerted their highest efficiency at 1% concentration (CTDs were 3.63, 0.79 and 0.80 adults, respectively). On another hand, tri-ammonium phosphate, ammonium carbonate and ammonium acetate attracted females more than males. While, the rest of tested compounds' concentrations attracted both sexes with no significant differences between them.