An absorbent sanitary article comprising: - a chassis having a longitudinal axis, two side edges, a rear waist section, a front waist section and a crotch section intermediate between the rear waist section and the front waist section, wherein the chassis comprises a topsheet having an outer surface which, during use, faces the user's body, a backsheet and an absorbent core interposed between the topsheet and the backsheet, - at least one pair of side panels (59, 60) extending laterally outwards from the respective side edges of the chassis in at least one of the rear and front waist sections (16, 18), wherein said side panels (59, 60) have respective proximal edges fixed to the chassis and respective elastic portions elastically extendable along a transverse direction perpendicular to said longitudinal axis, and - at least one gasketing element applied to the outer surface of the topsheet in at least one of said rear and front waist sections (16, 18), wherein said at least one gasketing element has an outer transverse edge, an inner transverse edge and two side edges, wherein the outer transverse edge is attached to the chassis and the inner transverse edge is detached from the outer surface of the topsheet to form a pocket open towards said crotch section, and wherein at least one of said side edges of the gasketing element extends in a transverse direction beyond the respective side edge of the chassis, and is fixed to a respective side panel (59, 60), wherein at least part of the elastic portion is arranged between said side edge of the gasketing element and said proximal edge of said respective side panel (59, 60). - a chassis having a longitudinal axis, two side edges, a rear waist section, a front waist section and a crotch section intermediate between the rear waist section and the front waist section, wherein the chassis comprises a topsheet having an outer surface which, during use, faces the user's body, a backsheet and an absorbent core interposed between the topsheet and the backsheet, - at least one pair of side panels (59, 60) extending laterally outwards from the respective side edges of the chassis in at least one of the rear and front waist sections (16, 18), wherein said side panels (59, 60) have respective proximal edges fixed to the chassis and respective elastic portions elastically extendable along a transverse direction perpendicular to said longitudinal axis, and - at least one gasketing element applied to the outer surface of the topsheet in at least one of said rear and front waist sections (16, 18), wherein said at least one gasketing element has an outer transverse edge, an inner transverse edge and two side edges, wherein the outer transverse edge is attached to the chassis and the inner transverse edge is detached from the outer surface of the topsheet to form a pocket open towards said crotch section, and wherein at least one of said side edges of the gasketing element extends in a transverse direction beyond the respective side edge of the chassis, and is fixed to a respective side panel (59, 60), wherein at least part of the elastic portion is arranged between said side edge of the gasketing element and said proximal edge of said respective side panel (59, 60).