OBJECTIVE: To investigate the characteristics of chronic frontal sinusitis and to improve the clinical therapeutic efficacy. METHOD: Sixty-eight patients (130 sides) who underwent endoscopic frontal sinus surgery in our department were randomly divided into three groups: Group 1 included 23 patients (43 operations) underwent endonasal sinus surgery with the frontal sinus opened and drained by two pipes of silicone for 6 months. Group 2 included 24 patients (45 operations) treated as group 1 but added injection of beclomethasone (approximately 1 cc, 94 mcg/100 microliters). Group 3 included 21 patients (42 operations) with only frontal sinus opened. RESULT: After an average follow-up of 18 months, the cute rate in group 1, group 2 and group 3 was 93%, 93% and 71% respectively. CONCLUSION: The ultimate success or failure of frontal sinus surgical procedures, whether they are endonasal or external, depends on the restenosis of the frontal sinus outflow tract or neo-ostium postoperatively. Long-term stenting for a period of several months will significantly reduce the possibility of restenosis. We recommend that this type of management be considered in difficult revision cases and before performing an external operation.