The present invention relates to a crane having a boom at which at least one load receiving means is arranged in a raisable and lowerable manner, wherein an overload protection device has detection means for detecting the outreach and the load on the at least one load receiving means, and wherein a monitoring device for monitoring the overload protection device is provided and has determination means for determining a tensioning force holding the boom and/or induced in a guy cable. The invention furthermore also relates to a method for monitoring the overload protection device of such a crane. Provision is made in accordance with the invention that the monitoring device determines online in crane operation a tensioning torque from the continuously determined tensioning force, determines a lifting torque from the continuously detected outreach and the continuously detected load, determines a dead torque while making use of stored crane data, compares the sum of the named lifting torque and the named dead torque with the named tensioning torque and then, if a difference found in the comparison exceeds a tolerance threshold, emits an error signal and/or shutdown signal.