The use of aluminum tailor welded blanks in the automotive industry continues to grow due to the fact that aluminum is lightweight and the characteristics of the tailor welded blanks. It has been found that welding of aluminum blanks with a CO2 laser is difficult but doable in a production environment. By using a high power CW Nd:YAG (Neodynium dopped Yittrium Aluminum Garnet) laser. It is possible to obtain sound results with a much wider process parameter window. However, currently, high power CO2 lasers (in the range of 8 kW) are still the dominate laser source in North America steel tailor welded blank companies. Will these lasers be able to weld aluminum tailored blanks if the demand for aluminum tailor welded blanks increases? This study employed twin spot and beam shaping methods to weld 1mm and 2 mm tailored blanks together using a high power (9 kW maximum) CO2 laser for both 5754-O and 6111-T4 alloys. The results show that high power CO2 lasers can be used to weld 5754-O and 6111-T4 aluminum alloys with very precise parameter settings. However, using beam shaping is more critical than using twin spot for 1 mm thick aluminum blanks. Once the correct parameters are applied for using beam shaping, the cup test results are better than using twin spot.