Abstract: An improved trailer for transporting bulk seed boxes is provided. The trailer includes a bed, a hopper extending below the bed for receiving seed from the bulk seed box, and an auger for unloading seed from the hopper. The bed includes upwardly and outwardly extending guide plates to provide self-centering of the seed box when the box is loaded onto the bed with a forklift truck. The bed includes lock bars moveable between locked and unlocked positions to secure the seed box to the bed. The hopper includes a slide gate with a control arm connected to the gate and extending to the auger side of the trailer for moving the slide gate between open and closed position. The auger includes a foldable upper section which is pivotal between a folded transport position and an extended raised operative position. The folding of the upper auger section is facilitated by a gas cylinder and a lever arm.