In this work, the influence of a bulge in the molten pool on solidification flaw formation was analyzed, and how some parameters affect the bulge and the amount of solidification flaws in hybrid laser-GMA welding of API 5L X70 steel. The welding parameters were varied, concerning filler wire material, laser beam power, welding speed, beam width and the use of transverse beam oscillation, and then the weld seams were submitted to X-ray and metallographic imaging. The bulge widening angle, proposed as a means of evaluating the correlation between the bulge and the solidification flaw formation, yielded good results.