A method for welding profiled elements made of a plastic material, in particular PVC, comprising the steps of: - preparing at least two profiled elements made of a plastic material, arranged with respective zones to be welded facing one another; - heating said zones to be welded; - coupling the zones to be welded to one another, by pressing the profiled elements against one another to keep the zones to be welded in reciprocal contact; - said step of coupling the zones to be welded defining a sub-step of melting the zones to be welded into one another to define a welding bead; and - before the heating step, the step of making a groove in correspondence to a peripheral edge of each of said zones to be welded; characterized by the fact that said step of coupling the zones to be welded comprises the sub-steps of: - arranging pressing means (27, 28) in correspondence to said grooves to define, in collaboration with said grooves, at least a containing compartment of said welding bead, said pressing means (27, 28) comprising: - at least a first work surface having a protruding portion; and - at least a second work surface of final finishing; and - displacing said pressing means (27, 28) alternately between: - an idle position moved away from said profiled elements; - a first work position wherein said first work surface is abutted on said grooves with said protruding portion located at least in part inside said containing compartment to deviate said welding bead towards the side walls of said containing compartment; and - a second work position wherein said second work surface is abutted on said grooves so as to obtain a finished welding bead. - preparing at least two profiled elements made of a plastic material, arranged with respective zones to be welded facing one another; - heating said zones to be welded; - coupling the zones to be welded to one another, by pressing the profiled elements against one another to keep the zones to be welded in reciprocal contact; - said step of coupling the zones to be welded defining a sub-step of melting the zones to be welded into one another to define a welding bead; and - before the heating step, the step of making a groove in correspondence to a peripheral edge of each of said zones to be welded; - arranging pressing means (27, 28) in correspondence to said grooves to define, in collaboration with said grooves, at least a containing compartment of said welding bead, said pressing means (27, 28) comprising: - at least a first work surface having a protruding portion; and - at least a second work surface of final finishing; and - at least a first work surface having a protruding portion; and - at least a second work surface of final finishing; and - displacing said pressing means (27, 28) alternately between: - an idle position moved away from said profiled elements; - a first work position wherein said first work surface is abutted on said grooves with said protruding portion located at least in part inside said containing compartment to deviate said welding bead towards the side walls of said containing compartment; and - a second work position wherein said second work surface is abutted on said grooves so as to obtain a finished welding bead. - an idle position moved away from said profiled elements; - a first work position wherein said first work surface is abutted on said grooves with said protruding portion located at least in part inside said containing compartment to deviate said welding bead towards the side walls of said containing compartment; and - a second work position wherein said second work surface is abutted on said grooves so as to obtain a finished welding bead.