OBJECTIVE To examine the factors which affect the improvement or the recurrence of disease after intralesional steroid injection in patients with oral lichen planus (OLP). METHODS Sixty-two patients diagnosed as OLP were treated with intralesion corticosteroid injection. To evaluate the objective severity of OLP, total severity score of OLP was assessed. To examine the factors affecting the therapeutic effect of intralesional steroid injection, factors were compared between the symptom-improved group and symptom-not-improved group. To assess the symptom of patients, patients filled in 10-cm visual analogue scale, along with an Oral Health Impact Profile-14. RESULTS Symptoms improved in 50 patients (80.6%, symptom-improved group), but not in 12 patients (symptom-not-improved group). In a comparison between both group, OLP with lip involvement was the only variable which showed significant difference (P=0.008). Twenty-nine of 50 patients had recurrence of OLP (58%, recurrence group) and 21 of 50 patients did not have recurrence (42%, no-recurrence group). Statistically significant differences were not found between both groups. CONCLUSIONS This study suggested that patients suffering from OLP with lesion on the lip might not be effective in treating with intralesional corticosteroid injection.