There have been tremendous studies on mechanical properties of welded 2024 aluminum alloys with coarse grain size structure. However, for structures characterized with bimodal grain size distribution, (i.e. Ultrafine / micro grain size) it needs more investigations. Such structures have been reported to exhibit great mechanical and physical properties. In order to compensate poor mechanical properties of 2024 aluminum alloy, in this research, aluminum samples were initially produced with bimodal structure by employing cry-rolling practice. 2024 aluminum alloy with the dimension of 80 mm × 50 mm × 8 mm were cryorolled with 85% reduction, and then for generation of bimodal structure which in turn could result in simultaneous strength and ductility, samples were aged for 6 hours at temperature of 160 0 C. Microstructural observations and phase analysis results after the rolling showed bimodal structure including ultrafine-grain along with grains in the size of micrometer, and also Al 2 CuMg-strengthening precipitations in the size of 30-50 nm. The tensile strength, hardness and ductility values of 552 MPa, 170 HV and 10%, respectively, were obtained. The first two were considerably increased whereas the ductility was slightly decreased. Due to high sensitivity of ultrafine-grain materials to temperature, Resistant Spot Welding joining process was used, having minimum exposure time and small weld pool size. All samples were joined employing welding parameters contained 3 kN electrode force, 0.1 S time and 55-105 kA welding current. According to mechanical tests, the best welding current of 95 KA for cryorolled samples, and also cryorolled and aged samples was determined. Maximum fracture force values of 5400 N and 4920 N were achieved for the above mentioned samples, respectively. On the other hand, the maximum fracture force value of 4280 N was examined for 2024-T3 aluminum samples welded with the current of 85 KA. It was also observed that larger size of weld nugget in cryorolled samples resulted in increasing in strength comparing to the one for other samples. Furthermore, similar hardness values were obtained in weld areas of all three samples, having lower hardness than those of the base materials. All three samples showed interfacial fracture mode after tensile tests. In addition, resolving of Al 2 CuMg strengthening precipitations (detected by phase analysis) led to hardness decrease in the melted zone.