Tube hydroforming is one of the manufacturing processes to produce lightweight components for automotive and aerospace industries. In this process a fluid medium is used to form a component either with high or low internal pressure. This process has gained popularity due to its many advantages such as part consolidation, quality of the formed part, and the possibility of unique shapes with indents or angles. In low-pressure tube hydroforming, the tube is marginally pressurized to a fixed volume during the closing of the die. Tube hydroforming can produce many geometric options which reduces the need for welding operations. The success of the tube hydroforming process is contingent on the ideal combination of material properties, process limitations, process sequence, and die geometry. The focus of this paper is to investigate the effect of preform on the low-pressure tube hydroforming in terms of pressure requirement, buckling and die filling. For this, a plain strain 2D model was created and hydroforming process was simulated. The tube was preformed to various widths and then hydroformed using low pressure. Two pressure conditions were simulated. The thickening of tube was observed which resulted in buckling of the tube. With higher pressure the buckling reduced but thickening of tube increased.