A novel and cost-effective foam injection molding process using gas-laden pellets has been developed. In order to further improve this new technology for industrial scale applications, in this study, two types of additives were introduced into the process: a) talc as a nucleating agent to enhance the cell nucleation rate, and b) low molecular weight additives to suppress the gas desorption process from the gas-laden pellets. The experimental results show that by blending 2% of talc, significant improvement in cell morphology and part weight reduction can be generated. Two types of low molecular weight additives, namely ethylene bis-stearamide (EBS) and oleamide were compounded with polypropylene (PP) to form crystalline layers inside and at the surface of the gas-laden pellets, which effectively prolongs the shelf life, as well as leads to a smaller process variation.