A game cart bicycle attachment device is provided that is configured to secure the handle end of a wheeled game cart to the seat post of a bicycle. The device comprises an elongated and angled member that attaches at a first end to the bicycle seat post and at a second end to a game cart. The second end comprises a T-shaped connection, whereby a lateral attachment bar attaches to opposing sides of the game cart and the angled member connects at a third location. The angled member includes a telescoping structure to offset the game cart, while furthermore the lateral attachment bar is telescopically adjustable to accommodate different game cart sizes. The ends of the lateral attachment bar include U-shaped clevises, while a third clevis is adjustably disposed along the angled member. The device therefore attaches to the game cart at three distinct locations along its U-shaped handle.