Reviewed are three technologies for welding of polyethylene pipes with each other and with connecting parts: electric welding, joint welding and socket welding. It is noted, that these welding technologies are not competitive, but mutually complete each other depending on conditions of application. it is stated, that for construction of new polyethylene gas pipe-lines and for reconstruction of pipe-lines parts, lying within the limits of populated areas, electric welding is the most effective, as well as socket welding technology for the parts of the pipe-lines, lying between populated areas.