Horizontal refrigerated showcase, comprising: - a base wall; - four transparent lateral walls, each fixed substantially perpendicular to the base wall, such that the showcase has a substantially parallelepipedic shape; - an opening/closing system of the showcase, arranged opposed in respect to the base wall, wherein the opening/closing system comprises a plurality of transparent panes (G1, G2) arranged in parallel planes, each pane (G1, G2) having a substantially rectangular shape, - each pane (G1, G2) resting on two of its opposed sides, along the entire length of said sides, on a respective sliding path (C12, C23), - each pane (G1, G2) being capable to move in its own plane, on the respective sliding paths, in a direction that is the same with the direction of the sides resting on the sliding paths (C12, C23), - wherein the sliding paths (C12, C23) are attached respectively to two opposed lateral walls of the showcase, walls that are parallel to the panes (G1, G2) moving direction, characterized in that - each transparent lateral wall corresponding to the sliding paths (C12, C23) consists of transparent parallel panels (P1, P2, P3) having ascending heights starting with the innermost panel and ending with the outermost panel, - the transparent panels (P1, P2, P3) being kept appart from each other by means of transparent spacers (D12, D23) arranged such that the upper surface of each spacer (D12, D23) serves as a sliding path (C12, C23) for a respective pane (G1, G2). - a base wall; - four transparent lateral walls, each fixed substantially perpendicular to the base wall, such that the showcase has a substantially parallelepipedic shape; - an opening/closing system of the showcase, arranged opposed in respect to the base wall, wherein the opening/closing system comprises a plurality of transparent panes (G1, G2) arranged in parallel planes, each pane (G1, G2) having a substantially rectangular shape, - each pane (G1, G2) resting on two of its opposed sides, along the entire length of said sides, on a respective sliding path (C12, C23), - each pane (G1, G2) being capable to move in its own plane, on the respective sliding paths, in a direction that is the same with the direction of the sides resting on the sliding paths (C12, C23), - wherein the sliding paths (C12, C23) are attached respectively to two opposed lateral walls of the showcase, walls that are parallel to the panes (G1, G2) moving direction, characterized in that - each pane (G1, G2) resting on two of its opposed sides, along the entire length of said sides, on a respective sliding path (C12, C23), - each pane (G1, G2) being capable to move in its own plane, on the respective sliding paths, in a direction that is the same with the direction of the sides resting on the sliding paths (C12, C23), - wherein the sliding paths (C12, C23) are attached respectively to two opposed lateral walls of the showcase, walls that are parallel to the panes (G1, G2) moving direction, - each transparent lateral wall corresponding to the sliding paths (C12, C23) consists of transparent parallel panels (P1, P2, P3) having ascending heights starting with the innermost panel and ending with the outermost panel, - the transparent panels (P1, P2, P3) being kept appart from each other by means of transparent spacers (D12, D23) arranged such that the upper surface of each spacer (D12, D23) serves as a sliding path (C12, C23) for a respective pane (G1, G2).