In this communication, design of asymmetrical multiple open slot loaded microstrip antenna for WiBro/WiMAX/WLAN band operation is presented. The substrate material is chosen as FR4 ([Formula: see text], [Formula: see text]) and fed by coaxial feeding. This antenna is able to radiate at four resonating bands. The antenna is radiating between 2.29 and 2.39 GHz, which is suitable for Wireless Broadband, WiBro. In parallel to this design, this antenna is also radiating in (5.16–5.36 GHz and 5.725–5.825 GHz) range which cover Wireless Local Area Network, WLAN (5.2/5.8 GHz) bands. Moreover, this antenna is radiating in (3.28–3.65 GHz, 5.45–5.65 GHz) range which is suitable for Worldwide Interoperability for Microwave Access, WiMAX (3.5/5.5) GHz bands. Measured results have proven that there is a good agreement with the simulated results of farfield patterns, reflection coefficient, peak gain of the proposed asymmetrical multiple open slot loaded microstrip antenna. The volume of this design is [Formula: see text]. Radiation pattern is noticed as stable at all obtained resonating frequencies. Maximum gain of 4.2 dBi is achieved between 3.28 and 3.65 GHz frequency band.