•Cryo-EM ?3 adrenergic receptor structure complexes with mirabegron and G?s•Mirabegron adopts an elongated shape fits vertically within the pocket•Interactions essential for activation in orthosteric site are identified•The narrower exosite of accounts ?3AR-selectivity The ?3-adrenergic (?3AR) is predominantly expressed adipose tissue urinary bladder has emerged as attractive drug target treatm...