The protection system (5) comprises a first tubular member (13) and a second tubular member (15) which can be slidably inserted into each other and a protection (8) at one end of the first tubular member (13). The protection comprises a protective boot (40) and a first annular element (21) fixed to the first tubular member (13). Further provided for is a second annular element (33) which can be torsionally coupled to the first annular element (21) and which can be decoupled therefrom by means of a mutual movement between the first annular element (21) and the second annular element (33) in a direction approximately parallel to the axis (A-A) of the first tubular member (13). The second annular element (33) is coupled to the protective boot (40) which is provided with members (49) for coupling to a stationary plate (51) which can be connected to a power take-off (9). A drive shaft provided with such a protection system is also described.