BACKGROUND We aimed to quantify the severity of the hallux valgus based on the lateral sesamoid position and to establish a correlation of our simple assessment method with the conventional radiological assessments. METHODS We reviewed one hundred and twenty two dorso-plantar weight bearing radiographs of feet. The intermetatarsal and hallux valgus angles were measured by the conventional methods; and the position of lateral sesamoid in relation to first metatarsal neck was assessed by our new and simple method. RESULTS Significant correlation was noted between intermetatarsal angle and lateral sesamoid position (Rho 0.74, p < 0.0001); lateral sesamoid position and hallux valgus angle (Rho 0.56, p < 0.0001). Similar trends were noted in different grades of severity of hallux valgus in all the three methods of assessment. CONCLUSIONS Our method of assessing hallux valgus deformity based on the lateral sesamoid position is simple, less time consuming and has statistically significant correlation with that of the established conventional radiological measurements.