 This study aimed to develop an effective method for delivering an anti-cancer drug 5FU and Myrna inhibitor oligonucleotide, Myr-21i, to her two expressing cancer cells. Engineered exosomes were used to simultaneously deliver 5FU and Myr-21i to 5FU-resistant colorectal cancer cell-line HCT-1165FR. The results showed that the engineered exosome-based 5FU and Myr-21i co-delivery system could efficiently facilitate cellular uptake and significantly down-regulate Myr-21 expression in 5FU-resistant HCT-1165FR cell lines. The down-regulation of Myr-21 induced cell cycle arrest, reduced tumor proliferation, increased apoptosis and rescued PTEN and HMSH2 expressions, regulatory targets of Myr-21. Furthermore, the combinational delivery of Myr-21i and 5FU with the engineered exosomes effectively reversed drug resistance and significantly enhanced the cytotoxicity in 5FU-resistant colon cancer cells, compared with the single treatment with either Myr-21i or 5FU. The study suggests that the strategy for co-delivering the functional small RNA and anti-cancer drug by exosomes could be a potential approach to reverse the drug resistance in CRC and enhance the efficacy of cancer treatment.