The theme of this thesis is „GMAW welding of Al alloys“. It is divided into two parts, the first one being theoretical and the second experimental. The theoretical part describes the character and properties of aluminum and its alloys with special emphasis on the application of aluminum alloys in shipbuilding. It briefly explains the welding processes used for aluminum alloys, such as TIG, the arc plasma welding (PAW), laser and friction stir welding, furthermore it contains detail description of GMAW welding process. The final section gives an overview of recommended types of joint preparation for GMAW or GTAW process on aluminum alloys according to HRN EN ISO 9692-3. In the experimental part, sheets made out of aluminum alloy EN AW 5083 were butt welded, one pair of sheets using ceramic backing material and the other using copper backing plate. Aluminum sheets were prepared according to HRN EN ISO 9692-3 standard. Welding was done using GMAW pulse technology. We tested welds using non-destructive dye penetrant method and root and face bend tests, as well making the microscopic analysis. Based on the results of experimental work the conclussion was made.