A mechanism for closing sliding doors of furniture. The mechanism includes at least two rotatable closing elements, each associated with a respective door. A locking body is associated with the closing element for rotating and locking the closing element in either an open position or a closed position. The closing element also includes a locking portion that, through the rotation of the closing element, can pass from a first position in which the locking portion prevents the translation of the sliding doors of the furniture, to a second position which allows the translation of the sliding doors. The closing mechanism also includes a synchronization bar that makes the closing elements rotate as a unit, ensuring the simultaneous locking of the sliding doors in the closed or open position.