A system for composting (I) organic waste including a chassis (A) delimiting a space dedicated to the composting (II) of organic waste and in which are disposed; - an upper composting compartment , mounted on the chassis (A) and having, opposite a movable bottom , a receiving section for the organic waste able to be obturated by a closing wall (F), the movable bottom occupying either an open position delimiting a discharge section for the organic waste by dropping the compost or a closed position to obdurate the discharge section ; - at least one drawer-type intermediate composting compartment , disposed below the upper composting compartment , and having, opposite a movable bottom , an opening section adapted to receive the waste coming from the discharge section of the upper composting compartment , this intermediate composting compartment being mounted on the chassis (A) by a sliding connection with a horizontal axis allowing it to occupy either a retracted position in which the opening section is located in line with the discharge section of the upper composting compartment or a position pulled out of the chassis (A) to access the interior of the intermediate composting compartment , the movable bottom occupying either an open position delimiting a discharge section for the organic waste by dropping the compost or a position closed to obturate the discharge section ; - a composting compartment with movable bottom including a sliding connection between a frame and a movable bottom , the sliding connection between the frame and the movable bottom of a composting compartment including rails fixed on the inside of the side edges (1H, 1I and 2H, 2I) of the movable bottom and cooperating with complementary rails fixed on the outside of the side walls of the frame ; - and a lower composting compartment , disposed at the bottom of the space dedicated to the composting (II), having an opening section located in line with the discharge section of the intermediate composting compartment located above. - an upper composting compartment , mounted on the chassis (A) and having, opposite a movable bottom , a receiving section for the organic waste able to be obturated by a closing wall (F), the movable bottom occupying either an open position delimiting a discharge section for the organic waste by dropping the compost or a closed position to obdurate the discharge section ; - at least one drawer-type intermediate composting compartment , disposed below the upper composting compartment , and having, opposite a movable bottom , an opening section adapted to receive the waste coming from the discharge section of the upper composting compartment , this intermediate composting compartment being mounted on the chassis (A) by a sliding connection with a horizontal axis allowing it to occupy either a retracted position in which the opening section is located in line with the discharge section of the upper composting compartment or a position pulled out of the chassis (A) to access the interior of the intermediate composting compartment , the movable bottom occupying either an open position delimiting a discharge section for the organic waste by dropping the compost or a position closed to obturate the discharge section ; - a composting compartment with movable bottom including a sliding connection between a frame and a movable bottom , the sliding connection between the frame and the movable bottom of a composting compartment including rails fixed on the inside of the side edges (1H, 1I and 2H, 2I) of the movable bottom and cooperating with complementary rails fixed on the outside of the side walls of the frame ; - and a lower composting compartment , disposed at the bottom of the space dedicated to the composting (II), having an opening section located in line with the discharge section of the intermediate composting compartment located above. <EOS>