Loop-mediated isothermal amplification (LAMP) for the detection of Cronobacter sakazakii in milk powder was successfully developed. For the reliable detection of C. sakazakii, LAMP primer sets targeting the outer membrane protein A (ompA) gene of C. sakazakii were designed using Explorer V4 software. Thirty-seven C. sakazakii strains and 13 pathogenic microorganisms were used for comparative detection of C. sakazakii via polymerase chain reaction (PCR), real-time PCR, and LAMP. The LAMP method developed in this study could specifically detect C. sakazakii strains without cross-reactivity with other foodborne pathogens. LAMP products amplified from the ompA gene of C. sakazakii were digested with HhaI and NruI enzymes. The specificity of LAMP was confirmed by restriction fragment length polymorphism (RFLP) analysis. LAMP could detect C. sakazakii within 1 h without the need for bacterial culture, with a detection limit as low as 1 CFU/mL of C. sakazakii in milk. In terms of sensitivity, LAMP showed a detection limit 10,000 times and 100 times lower than that of PCR and real-time PCR, respectively. Therefore, this study concludes that LAMP is a rapid and reliable detection technique for identifying C. sakazakii contamination in powdered milk.