Abstract: The implementation of lean concepts is to reduce or eliminate the wastes that occur during production process. One common form of waste that occurs frequently is waste caused by product defects. The object of this research is packaging process at a company that specializes in the processing of milk powder. The objective of this research is to find out the sources of defects due to sealing failure, and then develop the proposed remedial action plan to reduce these defects. Research data has been collected and analyzed quantitatively and qualitatively by quality control tools. It was found there are 11 known causes of failed seals, and the main causes are the condition of the sealer, cutting knife, and the characteristics of semi-finished products. The study concluded 13 corrective action plans, focused on increasing skills and awareness of operators, standardization and size of packaging machinery, and machine maintenance. It is also estimated that the remedial actions will result in reduction of defective products due to failed seals by 71.5% or a savings of 10.75 tons of powdered milk per month.