Inhalation therapy is an effective treatment for obstructive respiratory diseases in infants. It requires adequate knowledge and skiils on the p r ocedure from parents or caregivers [operators). The objective of this study was to describe the kind of errors that ihis late make while giving inhalation therapy to their infants. The administration technique of inhalation by operators, mainly mother, to 65 infants was observed in the setting of two general and one respirato-y cut patient clinics. The kind an magnitude of mistakes, their whole frequency and the global quality of each procedure according to a standard seven stages administration schedule were recorded at an out patient visit in the presence of two investigators and compared oy age and instruction of operators, previous knowledge of inhalation t-erapy and number of children under her [his) care. Operators made technical mislakes in 60% of cases and 36,9% of the treatments we r e considered unsuitable independently of operator's age, instructional level, previous experience and number of children under her |his) care.(