CT-scan was used to examine rhinosinusitis in the developing sinuses; 196 children aged from 3 to 14 years were selected on the base of their chronic rhinorrhea, nasal congestion and cough. The patient group was subdivided into six age groups (3-4, 5-6, 7-8, 9-10, 11-12 and 13-14 years). In the youngest age group, the authors noted maxillary involvement in 63%, ethmoidal involvement in 58%, and even sphenoidal sinus involvement in 29% of the children. Involvement decreased gradually with age, with 10% of ethmoidal and 0% of sphenoidal involvement in the 13-14 years age group. Maxillary sinusitis, however, persisted very frequently in the oldest age group (65%). Frontal involvement seems to become significant at the age of 7-8 years (7%) but it never exceeds 15% (11-12 age group). Septal deviations occurred in 16% of the youngest up to 72% in the oldest age group. A prevalence of bullous conchae increased with age too, although less prominently.