Background Inhaled corticosteroids have become the mainstay of asthma therapy. Few studies however, have compared inhaled steroids in children. We compared the efficacy of inhaled fluticasone propionate (FP), 880 μg/day (2 puffs of 220 μg/puff, BID) with inhaled flunisolide (FLU), 1500 μg/day (3 puffs of 250 μg/puff, BID). Methods Thirty children with moderate to severe asthma, mean age 12.7 years (range 10 to 17 years), mean duration of asthma 8.4 years, initially received flunisolide 1500 μg/day for 1 year, and then were switched to fluticasone propionate 880 μg/day and followed for an additional year. Pulmonary function tests (PFTs) were monitored and analyzed before and after the switch for the duration of study. Mean percent predicted for age values for FVC, FEV 1, FEF 25-75%, and FEFR were compared at 1 month, 2 to 6-month intervals, and 7 to 12-month intervals and during the same season of the year. Pulmonary function tests within 3 weeks of an exacerbation were not included in the study. The number of asthma exacerbations, emergency room visits, hospital admissions, and number of school days lost were also compared. Results There was significant improvement in mean asthma exacerbations/patient/year (1.7 ± 1.66 SD) versus (4 ± 2.6) ( P < .0002); mean emergency room visits/patient/year (0.23 ± 0.62) versus (1.2 ± 1.74) ( P = .004); mean hospital admissions for asthma/patient/year (0.2 ± 0.61) versus (1.13 ± 1.45) ( P < .0002); and number of school days lost/patient/year (1.4 ± 2.38) versus (7.93 ± 6.7) ( P < .0002) while patients were receiving fluticasone propionate as compared with flunisolide. Also, the mean percent values predicted for age in all time-periods (at 1 month, 2 to 6 months, and 7 to 12 months) revealed significant improvement in FEV 1 and FEF 25-75% ( P < .05 for both parameters). As PFT can be affected by seasonal changes, PFT parameters were compared during the same season of the year and significant improvement in FVC and FEV 1 was observed in all seasons while patients were receiving fluticasone propionate (FP) compared with flunisolide (FLU) ( P < .05 for all parameters). Significant improvement in PEFR and FEF 25-75% was observed only in spring and summer season. Conclusion Fluticasone propionate 880 μg/day improved lung function and quality of life in adolescents with moderate-to-severe asthma when compared with flunisolide 1500 μg/day.