Purpose: To evaluate the validity and intra-rater, inter-rater reliability of the EMC device used to check the mobility of the first ray of the foot. Materials and Methods: Sixty-nine cases (43 patients) of mild to severe hallux valgus feet were enrolled in this study. For an analysis of the validity of the EMC device, the dorsal mobility of the first ray of the foot was measured using the modified Coleman b lock test and EMC device. The intra- and inter-rater reliability of EMC device was evaluated by measuring the dorsal mobility of the first ray of the foot twice with three independent raters blinded to other's results. The results were analyzed for the intra-rater reliability and for inter-rater reliability. Results: The mean value of the dorsal mobility of the first ray of the foot by the EMC device and modified Coleman block test was 8.3 mm (range; 4.3-12.3 mm) and 7.4 mm (range; 3.4-10.3 mm), respectively. There was a significant difference between the EMC device and modified Coleman block test (p<0.05). However, both the measured data, showed a good correlation (Pearson cor- relation coefficient=0.84). The paired t-test for intra-rater reliability and ANOVA testing for inter-rater reliability showed no statistically significant difference. Conclusion: The EMC device is reliable and valid for measuring the mobilit y of the first ray of the foot.