Abstract: The invention provide isolated arrestin domain-containing protein 1 (ARRDC1)-mediated micro vesicles (ARMMs). Methods for generating and for isolating ARMMs are also provided herein. ARMMs can be used to deliver agents, for example, nucleic acids (e.g., siRNAs, microRNAs, lincRNAs), proteins (e.g., transcription factors, chromatin modulators, kinases, phosphorylases, or recombinases), or small molecules to target cells in vitro and in vivo, and methods for such ARMM-mediated delivery are provided herein. Diagnostic and therapeutic methods using ARMMs are also described herein.