Abstract: A flat bottom, stand-up bag and a method of manufacturing the bag is provided. The bag includes a bottom wall, opposing front and rear walls and two side walls. The side walls connect the front and rear walls and the bottom wall is connected to the other walls at their lower edge. The bag preferably incorporates a continuous polymer web material forming the front wall and rear wall of the bag, as well as the bottom wall. The side walls include gussets and a triangular base portion formed at the intersection between the bottom wall and the side walls.