A magnetic strap fastener for use with existing strapped articles without modification is presented. The fastener includes first and second fastener parts for attaching to a complementary engagement arrangement on first and second strap ends. The first and second fastener parts are detachably engageable with each other by magnetic coupling or attraction and include complementary engagement devices for detachable engagement with the corresponding complementary engagement arrangement on the strap ends. Such a fastener is advantageous because it offers the benefits of magnetic fasteners and is at the same time readily attachable to an article having strap ends with an existing pair of complementary engagement devices.