A drawbar pin adapter which can allow a smaller drawbar pin to be used with a larger drawbar. A drawbar pin adapter is provided for a tractor drawbar having a lower strap, an upper strap and a drawbar pin bore which extends through the upper and lower straps and which receives a drawbar pin. The adapter includes a cylindrical bushing mountable in the drawbar pin bore in the lower strap and a hollow housing which is mountable over the lower strap. The housing includes a lower plate, an upper plate and left and right side plates. The upper plate has an upper bore formed therein, and the lower plate has a lower bore formed therein. The upper and lower bores have a diameter which is smaller than an outer diameter of the bushing so that the upper and lower plates hold the bushing within the drawbar pin bore in the lower strap. The bushing and the upper and lower bores receive the drawbar pin when it is inserted through the upper and lower straps. A retainer retains the housing to the drawbar when the drawbar pin is removed from the drawbar pin bore. The retainer includes a cable coupled to the housing and looped around a portion of the drawbar.