Acanthamoeba is a free-living amoeba that can cause serious eye infection leading to blindness known as Acanthamoeba keratitis. The infection usually occurs amongst individuals wearing contact lenses. The use of contact lens disinfecting solution not effective against the Acanthamoeba cysts increases the risk for infection. There have been many studies indicating the resistance of Acanthamoeba cyst towards certain antimicrobial agents, enzymatic disinfectant and chemical disinfectant. Therefore, this study was performed to evaluate the efficacy of contact lens disinfecting solutions comprising Opti-Free® Express® & Complete™, against the cysts of Acanthamoeba. This study also investigates the effectiveness of the disinfecting solutions based on the soaking time recommended by manufacturers, 4 hours, 6 hours and 8 hours. Four clinical isolates of Acanthamoeba were tested in this study comprising HKL 11, HKL 51, HKL 32 and HKL 5. Ten microliter of cysts suspension (105 cells/ml) was tested on the disinfectant solution respectively. After an interval varying from 4 hours to 8 hours, the solutions were centrifuged and then the sediment was inoculated onto non nutrient agar lawn with E. coli. The plates were examined daily using inverted microscope for the emergence of Acanthamoeba trophozoites. The presence of Acanthamoeba trophozoites indicates that the cysts had successfully undergone excystation process denoting that the disinfecting solution is not effective. Opti-Free® Express® & Complete™ contact lens disinfecting solutions were not effective against all 4 isolates of Acanthamoeba cysts based on time recommended by manufacturers, 4 hours, 6 hours and even 8 hours soaking time. This study shows that there are more contact lens disinfecting solutions not effective against Acanthamoeba cysts compared to those that are effective.