This study investigated the efficacy of a system for continuous nebulization of terbutaline sulphate in the treatment of acute asthmatic crises in children. The equipment consisted of a condensation nebulizer attached to a 40 liter acrylic tent placed around the patient's head. A prospective, randomized and open clinical trial was conducted. Twenty eight children, 2 to 5 year-old, in acute asthmatic crises were selected. Fourteen were nebulized with terbutaline sulphate while in the control group the aerosolization was proceeded only with half diluted physiologic serum. All patients were administered aminophyline intravenously. The parameter used to evaluate the efficacy of the terbutaline sulphate nebulizing system was clinical improvement measured by the Wood-Downes Score. Two additional parameters indicating terbutaline sulphate absorption were used: reduction of potassium seric levels and positive chronotropic effect. The group treated with terbutaline sulphate showed greater clinical improvement than control group at the 12 hour protocol evaluation as well as lower seric potassium level. A positive chronotropic effect was also observed at the final protocol evaluation. The data showed, preliminarily, that (a) the system for continuous nebulization of terbutaline sulphate was effective in treatment of children's acute asthmatic crises, and (b) there was evidence attesting to the absorption of terbutaline sulphate by the children treatment with it.