Abstract: An alarm padlock (10) comprising a shackle (12) having a long leg (14) and a short leg (16). A body (18) is provided. A facility (20) in the body (18) is for mounting the shackle (12) in a reciprocal movement between a closed position and an extended open position, in which the short leg (16) of the shackle (12) is outside of the body (18) and the long leg (14) of the shackle (12) can swivel within the body (18). A latch mechanism (22) in the body (18) engages with the short leg (16) of the shackle (12), when the shackle (12) is in it's closed position. A lock mechanism (24) in the body (18) is operable to disengage the latch mechanism (22) from the short leg (16) of the shackle (12). An alarm circuit (26) in the body (18) actuates to emit a warning signal when an unauthorized person violates and tampers with the shackle (12) and the body (18).