During the period 1967 to 1978, 1166 girls were admitted to our department because of urinary tract infection. In 97 of the 439 girls examined by cystoscopy, cystitis cystica was found. The age of the 97 girls varied from 3 to 12 years, mean 7 1/2 years. E. coli was found to be the major pathogenic organism in the urine. All but 3 girls had a history of recurrent urinary tract infection. Urinary tract abnormalities were found with the same frequency as in other studies concerning urinary tract infection in childhood. Vesicoureteric reflux was demonstrated on the cystogram for 33% of the girls. Patients with cystitis cystica are a hard core group requiring long-term treatment and follow-up. Different therapeutic methods are discussed and our experience with chlorhexidine bladder instillation is mentioned. The literature concerning cystitis cystica, especially in childhood, is also discussed.