In this study, seven loaded atenolol (AT) nonionic microemulsions (MEs) were develop and evaluated in vivo and in vitro for transdermal application of atenolol with aid of nonionic surfactants. The MEs were characterized for their droplets sizes, rheological properties. Also, the FTIR was used for evaluation of encapsulation of AT in MES. Furthermore, the permeation of AT loaded MEs was studied through rat's skin in vitro using Franz diffusion cell over 24 hrs as well as in vivo in rats. The results show that AT loaded MEs have colloidal characteristics regarding their droplet size, transparency and rheological characteristics. Moreover, the FTIR showed that AT was inside the dispersed phase. The highest flux value for AT loaded MEs through the skin using Franz diffusion cell was 263.53 µg/cm2hr and the maximum plasma level of AT 4.17mg/ml was monitored after 7 hrs.