Piece of furniture of the type provided with compartments housing drawers and/or baskets and/or wing doors, in which said piece of furniture consists of a lower frame, a rear frame, an upper frame, lateral sides, characterised in that: i) said lower frame consists of a lower front section and of a lower rear section connected to each other by means of lower side sections orthogonally and internally placed with respect to said lower front and lower rear sections and fixed by means of means intended for the fixing. ii) said rear frame consists of an upper rear cross and a lower rear cross connected to each other by means of side stanchions orthogonally and internally placed with respect to said upper rear and lower rear crosses and fixed by means of means intended for the fixing, iii) said upper frame consists of an upper front cross on which upper side crosses are fixed by means of means intended for the fixing, said lower side sections and said side stanchions and said upper side crosses including seats intended to house by means of insertion said lateral sides, iv) said lateral sides being fixed on the lower side by means of means intended for the fixing inserted in holes obtained on the lower side of said lateral sides and by means of blocking means which fix said lateral sides on said lower side sections, v) said lateral sides being also fixed on the upper part by means of at least one means intended for the fixing inserted in an upper hole obtained on said lateral sides and by means of blocking means which fix said lateral sides on said upper side crosses -and further characterised in that said lateral sides essentially have a rectangular shape in which: - the rear lower edge is removed obtaining a rectangular shaped recess intended to allow the insertion of said lateral side into the seat of said lower side section; - the front lower edge is removed obtaining a rectangular shaped recess intended to allow the insertion of said lateral side into the seat of said lower side section; - the front upper edge is removed obtaining a rectangular shaped recess intended to allow the insertion of said lateral side into the seat of said upper side cross. i) said lower frame consists of a lower front section and of a lower rear section connected to each other by means of lower side sections orthogonally and internally placed with respect to said lower front and lower rear sections and fixed by means of means intended for the fixing. ii) said rear frame consists of an upper rear cross and a lower rear cross connected to each other by means of side stanchions orthogonally and internally placed with respect to said upper rear and lower rear crosses and fixed by means of means intended for the fixing, iii) said upper frame consists of an upper front cross on which upper side crosses are fixed by means of means intended for the fixing, said lower side sections and said side stanchions and said upper side crosses including seats intended to house by means of insertion said lateral sides, iv) said lateral sides being fixed on the lower side by means of means intended for the fixing inserted in holes obtained on the lower side of said lateral sides and by means of blocking means which fix said lateral sides on said lower side sections, v) said lateral sides being also fixed on the upper part by means of at least one means intended for the fixing inserted in an upper hole obtained on said lateral sides and by means of blocking means which fix said lateral sides on said upper side crosses -and further characterised in that said lateral sides essentially have a rectangular shape in which: - the rear lower edge is removed obtaining a rectangular shaped recess intended to allow the insertion of said lateral side into the seat of said lower side section; - the front lower edge is removed obtaining a rectangular shaped recess intended to allow the insertion of said lateral side into the seat of said lower side section; - the front upper edge is removed obtaining a rectangular shaped recess intended to allow the insertion of said lateral side into the seat of said upper side cross. - the rear lower edge is removed obtaining a rectangular shaped recess intended to allow the insertion of said lateral side into the seat of said lower side section; - the front lower edge is removed obtaining a rectangular shaped recess intended to allow the insertion of said lateral side into the seat of said lower side section; - the front upper edge is removed obtaining a rectangular shaped recess intended to allow the insertion of said lateral side into the seat of said upper side cross.