The purpose of this study is to investigate the relationship between the level of hardness or toughness evaluation and electromyography parameters of some Thai foods in 32 healthy young Thai adults who did not have masticatory problems. The subjects were given 5 Thai foods with different hardness and toughness to chew and afterward were tested for those levels by using visual analog scale (VAS) and electromyography. The result showed that the scores of each parameter obtained from VAS were significantly correlated with those obtained by electromyography (p<0.05, and r=0.224-0.384). A weak to moderate correlation between two test methods which may be due to the adaptability of masticatory muscles to the hardness and toughness of the food. Therefore, the evaluation of hardness and toughness level of food using a VAS questionnaire could partly reflect the functions of masticatory muscles.