The aim of this study was to determine the prevalence of renal scarring in a group of Kuwaiti Arab children with their first documented acute pyelonephritis (APN). Eighty-two Kuwaiti Arab children (10 males and 72 females) who had abnormal (99m)Tc DMSA renal scan findings of acute pyelonephritis were prospectively studied with the same imaging modality 6 months after treatment to identify those who developed renal scarring. A micturition cystourethrogram (MCUG) was performed for all of the children 1 month after diagnosis. Children were divided into 3 age groups (<2 years, 2-5 years and above 5 years). The follow-up DMSA renal scans 6 months after diagnosis revealed normalization of renal changes in 56% (46 patients), much improvement with residual renal abnormality in 6% (5 patients), and persistent parenchymal defects in 38% (31 patients). Vesicoureteric reflux (VUR) was found in 32% of children (26/82) and the majority were between grade I and III. Thirteen of those with VUR (50%) developed renal scars on follow-up. Fifty-three percent of the scarred kidneys (19/36) were drained by non-refluxing ureters. In this study, children older than 2 years had less VUR yet were more susceptible to APN and to the development of renal scars. Girls were more prone to developing APN and renal scarring than boys. This work shows that APN is a serious cause for renal scarring in our patients, particularly if associated with other risk factors such as recurrent infections and the female sex.