Abstract: Ergonomic chair-armchair structure, particularly for office, of the type with an adjustable kidneyrest and headrest, including a base with related support vertical column of a seat and a back, the latter of the type obtained by a tensioned sheet between the two sides of the chair-armchair, in which a support element of the headrest and of the kidneyrest, extended according to the profile of the back is closed to the back side of the latter, being, on one side, downwardly fixed to the seat, and on the other to a connecting cross element between the sides of the armchair; and furthermore in which said kidneyrest and headrest are adjustable along the said support element, providing selective locking means.