An adjustable retractable hinge for articulating a door to a fixed structure, comprising: - a first body , with a corresponding first containing housing , intended to be inserted within a corresponding first cavity obtained either in said fixed structure or in said door, - a second body , and a second containing housing , which houses said second body and which is intended to be embedded in a corresponding second cavity obtained either in said door or in said fixed structure, - three arms , shaped as a rocker and associated to said bodies so as to allow the rotation of the door with respect to said fixed structure, said three arms comprising two substantially equal outer arms , articulated to the first body and sliding along guides obtained in the second body , and a central arm , articulated to the second body and sliding along guides obtained in the first body , said second body comprising: - a central portion , facing said central arm and interposed between the outer arms , and provided with an element for fixing and adjusting said second body to said second containing housing , said element causing the movement of said second body in the direction of the either greater or lesser insertion depth in the corresponding second containing housing , - guiding means for said movement of said second body in the direction of its insertion in the corresponding second containing housing , said guiding means being arranged symmetrically with respect to said adjustment element , the hinge being characterized in that : the second body is made in one piece, and in that the element is a single element for fixing and adjusting said second body to said second containing housing (10, wherein the single element works as a single fixing element of said second body to the corresponding containing housing . - a first body , with a corresponding first containing housing , intended to be inserted within a corresponding first cavity obtained either in said fixed structure or in said door, - a second body , and a second containing housing , which houses said second body and which is intended to be embedded in a corresponding second cavity obtained either in said door or in said fixed structure, - three arms , shaped as a rocker and associated to said bodies so as to allow the rotation of the door with respect to said fixed structure, said three arms comprising two substantially equal outer arms , articulated to the first body and sliding along guides obtained in the second body , and a central arm , articulated to the second body and sliding along guides obtained in the first body , - a central portion , facing said central arm and interposed between the outer arms , and provided with an element for fixing and adjusting said second body to said second containing housing , said element causing the movement of said second body in the direction of the either greater or lesser insertion depth in the corresponding second containing housing , - guiding means for said movement of said second body in the direction of its insertion in the corresponding second containing housing , said guiding means being arranged symmetrically with respect to said adjustment element , the hinge being characterized in that : <EOS>