The study examined the perception of South-East Nigeria residents on Mobile Authentication Service (MAS) in detecting counterfeit pharmaceutical products. The study was anchored on the technological determinism theory and adopted the survey research design. The population for this study is made up of all residents of the five South Eastern states in Nigeria aged 18 and above, according to the National Bureau of Statistics, the projected population of the aforementioned states for 2021 are 23,856,937. The sample size for the study was 384. The sampling techniques used were purposive, cluster and accidental sampling technique. Findings from the study showed that that South East residents have negative attitudes towards the Mobile Authentication Service of NAFDAC because they believe it is useful in detecting counterfeit drugs, they know the steps involved but believe it is difficult to use and as such, they don’t tell others about it, which means silently rejecting the innovation of Mobile Authentication Service. The study recommended that to ensure that South East Residents develop a positive attitude towards the Mobile Authentication Service of NAFDAC, the Agency must constantly and consistently improve on how the service works.