Method for the manufacture of a knitted sock of the so-called invisible type, comprising a sock body having an opening or mouth for the introduction of a foot, said opening or mouth comprising a front part and a rear part, wherein the manufacture of the sock body comprises the steps of * manufacturing, using a circular knitting machine with latch needles: a decreased knitted heel portion, forming the rear part of said opening or mouth, an intermediate body portion, manufactured in continuation of the heel portion and forming the front part of said opening or mouth, and a toe portion, manufactured in continuation of the intermediate body portion; and * sewing to one another respective end edges or selvedges (5a, 6a) of the intermediate body portion and the toe portion; the method being characterized in that said circular knitting machine is supplied with a continuous yarn made of an adhesive synthetic material, and in that the upper part of the heel portion, which defines the rear part of said opening or mouth, is manufactured in said machine, using said yarn made of adhesive synthetic material; wherein said upper part of the heel portion comprises at least three knitted courses, corresponding to six strokes, and wherein said upper part of the heel portion is turned towards the outside, and its end edge or selvedge is attached to the outer surface of the heel portion, in such a way that said upper part of the heel portion has an essentially tubular configuration. * manufacturing, using a circular knitting machine with latch needles: a decreased knitted heel portion, forming the rear part of said opening or mouth, an intermediate body portion, manufactured in continuation of the heel portion and forming the front part of said opening or mouth, and a toe portion, manufactured in continuation of the intermediate body portion; and a decreased knitted heel portion, forming the rear part of said opening or mouth, an intermediate body portion, manufactured in continuation of the heel portion and forming the front part of said opening or mouth, and a toe portion, manufactured in continuation of the intermediate body portion; and * sewing to one another respective end edges or selvedges (5a, 6a) of the intermediate body portion and the toe portion; the method being characterized in that said circular knitting machine is supplied with a continuous yarn made of an adhesive synthetic material, and in that the upper part of the heel portion, which defines the rear part of said opening or mouth, is manufactured in said machine, using said yarn made of adhesive synthetic material; wherein said upper part of the heel portion comprises at least three knitted courses, corresponding to six strokes, and wherein said upper part of the heel portion is turned towards the outside, and its end edge or selvedge is attached to the outer surface of the heel portion, in such a way that said upper part of the heel portion has an essentially tubular configuration. the method being characterized in that said circular knitting machine is supplied with a continuous yarn made of an adhesive synthetic material, and in that the upper part of the heel portion, which defines the rear part of said opening or mouth, is manufactured in said machine, using said yarn made of adhesive synthetic material;