The present investigation aims to evaluate efficacy of adding some ammonium compounds to Conserve (GF-120) when used at different concentrations, (0.5, 1.0, 2.0 and 3.0% (wt./vol.) on attraction of the Mediterranean fruit fly (MFF). These compounds included; ammonium acetate (AA), Di-ammonium phosphate (DAP) and ammonium carbonate (AC). The relationship between attraction flies and pH values of the bait solution was also investigated. Field experiments were carried out at Dakahlia Governorate during October 2017 at Guava and Citrus orchards. The obtained results indicated a positive relationship between concentrations of all tested ammonium compounds and the number of attracted flies to GF-120 concentrations. Also, there were positive responses between pH values and the attracted flies (females, males or total). Females responded significantly more than males to pH values. Additions of 3% DAP or 2-3% AC to GF-120 enhanced its attraction to Ceratitis capitata, potentially increasing the bait's efficacy in applying integrated pest management programs for C. capitata.