62 patients (14 boys, 48 girls) representing 85 refluxive renal units (Grade 2-4) were investigated after successful operation for the development of further urinary tract infections (UTI) and renal scars (RS). The mean follow-up was 9.3 years. With the exception of one boy, none of the male patients developed any UTI or new RS. A similar result was obtained for about 45% of the girls. These two groups of patients presented with high-grade reflux before surgery. The remaining female patients (about 55%), however, presenting with lower-grade reflux before surgical treatment, developed further UTI as well as new RS despite surgical correction of their reflux. Investigations on the capacity of uroepithelial cells (UEC) to suppress bacterial growth revealed a deficient antibacterial effect of UEC in these patients. Such an UEC defect has also been shown in patients with asymptomatic bacteriuria. In conclusion, different reasons seem to be responsible for recurrent UTI and the development of RS in patients with reflux.