The mainstay of treatment in bronchiolitis includes oxygenation, aspiration of secretions from the respiratory tract and maintenance of hydration. The first choice medical agent in clinical practice is nebulized bronchodilators, although their place in treatment is controversial.We investigated the therapeutic benefit of nebulized hypertonic (3%) saline (HS), by comparing four different nebulized regimens in the treatment of bronchiolitis in the emergency department.A total of 120 infants were included in this randomized, double-blind, prospective study. Infants were grouped according to the nebulized treatment they received: group 1 - salbutamol + normal saline (NS), group 2 - salbutamol + HS, group 3 - HS, group 4 - NS. Heart beat, Clinical Bronchiolitis Severity Score (CBSS) and oxygen saturation of the patients were determined before and after the nebulizations and at 48-72 h after admission by the designated study physician.Post-treatment mean CBSS were significantly lower than pre-treatment scores in all groups (p = 0.0001) with no significant difference within groups. Improvement percentages for CBSSs were significantly higher in infants without a history of atopy treated with HS and NS (p = 0.023, p = 0.0001, respectively).The CBSSs of all the infants improved after three doses of nebulized therapy regardless of the treatment regimens. The combination of salbutamol with hypertonic saline did not lead to an additive effect in the improvement of CBSSs compared to the standard salbutamol + NS combination. Atopic children benefited from salbutamol/NS combination whereas non-atopic children improved with HS and NS nebulizations based on improvement percentages of CBSS.