Abstract: Application of ajoene to mayonnaise and its stability were studied. Addition of 5, 10, 15, 20, 25 and 30% garlic oil containing ajoene to mayonnaise recovered E-ajoene 47.7-62.4 μg/10g mayonnaise and Z-ajoene 42-74 μg/10g mayonnaise. After one month storage 99% E- and Z-ajoene remained. In 20% substituted mayonnaise 72% and 69% E- and Z-ajoene respectively were obtained at 80^oC. After three days incubation under UV-light and fluorescent light, 92% and 98% E-ajoene; 88% and 98% Z-ajoene respectively remained. Sensory evaluation demonstrated that, 20% substituted mayonnaise was the highest score among others.