In the present study, salep and chitosan hydrocolloid were used as stabilizers and FAT replacer in low-FAT mayonnaise and rheological and physicochemical characteristics were evaluated. FAT has been substituted with 0. 1, 0. 2 and 0. 3% chitosan and 6. 4, 0. 0, 0. 7, 1. 0 and 1. 3% salep. High-FAT mayonnaise sample or control with 67% FAT and without salep and chitosan(FF), mayonnaise with 67% FAT and 0. 4% salep and 0. 2% chitosan(F1), mayonnaise with 48% FAT and 0. 6% salep(F2), mayonnaise with 30% FAT and 1. 3% salep(F3), mayonnaise with 30% FAT and 1% salep and 0. 1% chitosan(F4), mayonnaise with 30% FAT and 0. 7% salep and 0. 2% chitosan(F5) and mayonnaise with 30% FAT and 0. 6% salep and 0. 3% chitosan(F6) were used as treatments of the present study. The results showed that salep and chitosan hydrocolloids could increase the viscosity of low-FAT mayonnaise samples by absorbing water as well as substitution role for FAT to increase the stability of low-FAT mayonnaise. Among the produced samples, F1 and F2 had the most similarity to the control sample. All the samples (both control ad low-FAT samples) did not have significant microbial load and the pH and acidity were at the allowed level. Creamy and phase separation phenomenon was not observed among the samples. Based on the results, it can be concluded that salep and chitosan hydrocolloids are proper substitutes for common high-FAT mayonnaises and can be employed in the formula of low-FAT mayonnaise without changing the qualitative features of the product significantly.