Good Manufacturing Practices (GMP) are guidelines in food production processes aimed at ensuring product safety, quality, and consistency. Evaluating GMP implementation is essential to identify non-conformance factors and develop corrective strategies. This study aims to evaluate GMP implementation in an instant noodle industry, PT. XYZ, using the fishbone diagram approach. The methodology involved in-depth interviews and observations as primary data sources, complemented by documentation studies and literature reviews as secondary data. The analysis revealed five main aspects influencing GMP effectiveness: man, method, machine, material, and environment. Contributing factors include inadequate training, weak monitoring systems, unhygienic machine design, non-standard raw materials, and suboptimal zoning and ventilation systems. The fishbone diagram effectively categorized root causes and served as a basis for designing corrective actions. Optimal GMP implementation is crucial for ensuring food safety, enhancing production efficiency, and maintaining the reputation of food industries in a competitive market.