Laser beam welding of relatively thin gage titanium is a robust process currently used on a variety of secondary structure aerospace applications.  Attempting to weld thicker, plate, gages for primary structure has presented more technical challenges associated with porosity formation and undercut.  In order to identify welding procedures capable of producing Class A welds, a study was conducted to explore the process window for laser welding 6 mm thick Ti-6Al-4V using a 10kW fiber laser.  Weld parameters of interest include laser spot size, power and travel speed.  It was found that high speeds, high powers and small spot sizes lead to welds with the least amount of porosity and under cut.  Hybrid-GMAW laser welding was also used to eliminate the remaining under cut inherent in the autogenous process.