The stability of an mRNA delivery system is critical for its practical applications. The greatest bottleneck for mRNA vaccines during the COVID-19 pandemic was the need for extremely cold storage temperatures in shipping. These temperatures were needed to ensure the viability of mRNA in the vaccine. Here in, we report the first long-term stability of mRNA encapsulated inside MOFs at various temperatures. We investigated the stability of the encapsulated mRNA over 12 weeks at room temperature, 4˚C, and -80˚C by taking mRPZ, drying it for 1 hour, and storing it. Room temperature storage condition was under vacuum as particles stored without vacuum had little transfection viability and formed cavities visible under TEM (Figure ). We believe the cavity formation is linked to the degradation of the mRNA, further validating the theory of a coreshell MOF particle. Interestingly, we found that after one month, the encapsulated mRNA transfected well across all temperatures, producing eGFP signals that were several folds above an untreated background sample (Figure ). However, at 8 and 12 weeks, a significant drop in the eGFP signal was observed in mRPZ stored at 4˚C and room temperature. mRPZ maintained its ability to successfully transfect cells even after 12 weeks at room temperature. When focusing on the stability of mRNA in mRNA-PEI versus mRPZ, a clear degradation of mRNA in mRNA-PEI was evident by 8 weeks, rendering it unable to transfect cells regardless of storage time or temperature (Figure ). The material stability of mRPZ was recorded over 3 months and compared to mRNA@ZIF-8 (Figure ). Notably, mRPZ and mRNA@ZIF-8 demonstrate a similar size and morphology at 1 month but more round morphologies at 3 months. The crystallinity was assessed using PXRD. mRPZ and mRNA@ZIF-8 demonstrate retention of the ZIF-8 diffraction pattern.