The injection compression molding (ICM), known as the low pressure process, becomes nowadays the frequently selected production process for optical parts or high aspect ratio parts where good optical properties, dimensional accuracy, and mechanical properties are inquired. Due to its low pressure characteristic and special process course, it is possible to produce plastic parts with a lower molecular orientation, reduced molded-in stress, sink mark, and warpage. With the ICM, the polymer melt is injected into the slightly opened mold and then compressed to the final thickness; thereby the melt shear flow effect is minimized. This is advantageous especially to thermally unstable polymeric materials like Polylactic acid (PLA), since this type of material usually prone to thermal degradation during the injection molding process(IM). According to this, Injection compression molding and injection molding of Polylactic acid packaging of different thicknesses were comparatively studied. In this study the experiments were designed using the Taguchi method and performed with three factors for the IM and five factors for the ICM at three levels each. It was found that the ICM could successfully produce PLA trays having higher flow length/wall thickness ratios (L/t) than did the IM. With the ICM remarkable L/t ratios of up to 215 were accomplished. Only trays with the thickness of 2.0 mm were completely formed by the IM, whereas trays with the thickness in the range of 0.4-2.0 mm could be produced successfully by the ICM. Moreover, better dimensional accuracy, higher tensile and flexural strength and lower % haze at the bottom of the trays were obtained by the ICM. However, advantages of the ICM over the IM were not significantly provided to the side wall properties.