Cereals and legumes constitute the staple foods in both urban and rural areas, and the main cereals and legume products in the Sahel region are millet, sorghum, maize, and cowpea. The small-scale processors of those products are facing storage and good packaging challenges. Triple hermetic bag technology is effective for the conservation of many stored grains against insect spoilage in Africa and around the world. This study aimed to examine the performance of the high-density polyethylene Purdue Improved Cowpea Storage (PICS) bags (HDPE, 80 microns thick) for the preservation of processed cereals (broken corn, millet pellet, and sorghum dagué) and legume (broken cowpea) products against insects of storage. In addition, the impact of this technology on the physical and functional parameters of the processed products (moisture content, pH, water-holding capacity, oil-holding capacity, and bulk density) after 6 months of storage was carried out. Rhizopertha dominica was revealed to be the damaging storage pest in the product of millet pellet and broken corn with the average number of live insects of 121.33 and 0.66, respectively, in experimentally designed bags. Significant differences (P < 0.01) and (P < 0.01) are found among the results of functional and physical properties tested on these processed products, using PICS bags versus other storage types of bags. The use of triple hermetic bag technology for storage of processed cereals and legume products has shown protection against damaging insects and preserved their physical and functional properties qualities.