The development of testicular hypotrophy (or testicular growth arrest) in pediatric patients with varicocele is the first indication for surgery. The aim of this study is to identify the correlation between grade of varicocele, grade of vein reflux and testicular growth arrest. Between 2000 and 2001, we recruited 226 patients affected by varicocele without testicular hypotrophy and with grades 2-3 spermatic vein reflux observed during Doppler velocimetry. Medical examinations carried out every 6 months allowed the assessment of varicocele grade, testicular volume, and grade of vein reflux. Other parameters considered in the study were: mean time of grade deterioration, mean time to onset of testicular growth arrest and the relationship between varicocele grade and testicular growth arrest. Deterioration of the condition was experienced in 92 patients (40%) in which 60 patients showed higher varicocele grades without testicular growth arrest, while 32 patients developed testicular growth arrest. There was a statistically significant relationship between testicular growth arrest and varicocele grades (grade 2 and 3) and between grade of reflux and testicular growth arrest. Although it is not possible to determine which patients will develop testicular growth arrest, the assessment of vein reflux allows the identification of those subjects who may potentially develop such a condition.