A stabilizing system for a self-propelled working machine such as a telescopic handler or the like, comprising a plurality of stabilizer arms able to be placed on the ground so as to enable stabilization of said machine and further comprising: one or more measuring devices able to detect a pressure to which said arms are subjected and to produce pressure signals according to said detected pressure; at least one processing unit connected to said measuring devices and comprising a position module configured to determine, based on said pressure signals, whether the arms are placed on the ground; and scissor stabilizers that include two pairs of said arms for stabilization, each of which is rotatable and that include a plurality of actuators suitable for determining the rotation of respective stabilizer arms and the lifting of said machine; wherein each stabilizer arm is telescopic and comprises at least one sleeve, in which an extractable element bearing a member for being placed on the ground, is slidably inserted substantially without any play, so as to enable extension or retraction of the arm; wherein said scissor stabilizers are equipped with a support element, for each pair of arms, said support element being intended to be fixed to the working machine and to which the sleeve of each arm is connected by means of a first hinge, and wherein a hydraulic cylinder is comprised in each actuator, the cylinder being connected by means of a second hinge to said support element and, by means of a third hinge to the sleeve of a respective arm; characterised in that at least one measuring device comprises a first extensometer pin included in said second hinge connecting a hydraulic cylinder and the support element. one or more measuring devices able to detect a pressure to which said arms are subjected and to produce pressure signals according to said detected pressure; at least one processing unit connected to said measuring devices and comprising a position module configured to determine, based on said pressure signals, whether the arms are placed on the ground; and scissor stabilizers that include two pairs of said arms for stabilization, each of which is rotatable and that include a plurality of actuators suitable for determining the rotation of respective stabilizer arms and the lifting of said machine; wherein each stabilizer arm is telescopic and comprises at least one sleeve, in which an extractable element bearing a member for being placed on the ground, is slidably inserted substantially without any play, so as to enable extension or retraction of the arm; wherein said scissor stabilizers are equipped with a support element, for each pair of arms, said support element being intended to be fixed to the working machine and to which the sleeve of each arm is connected by means of a first hinge, and wherein a hydraulic cylinder is comprised in each actuator, the cylinder being connected by means of a second hinge to said support element and, by means of a third hinge to the sleeve of a respective arm; characterised in that at least one measuring device comprises a first extensometer pin included in said second hinge connecting a hydraulic cylinder and the support element.