Aim: To evaluate the role of further grading of classical testicular microlithiasis (CTM) on the prevalence of associated testicular tumors. Methods: Patients diagnosed with CTM using scrotal ultrasound over a 5-year period from a referral radiology clinic were included in this study. Patients with CTM were categorized as group 1 (grade I; 5-10 microliths/image), group 2 (grade II 10-20 microliths/image), and group 3 (grade III > 20 microliths/image). Other pathological findings were also recorded. The prevalence of testicular cancer was compared statistically between groups using the chi(2) test. Results: Seventy-eight of 4,310 (1.8%) patients were found to have CTM. Of these, 17 (21.7%) had ultrasonographically detected testicular cancer. In patients without CTM (n = 4,232), 58 (1.1%) testicular cancers were found. This accounted to a 19.7-fold increase in the detection rate of testicular cancer in patients with CTM compared to patients without CTM. The rates of testicular cancer detected in groups 2 and 3 were 25 (6/24) and 26.6% (4/15), respectively (p > 0.05), while it was 17.9% (7/39) in group 1. Conclusions: CTM is an uncommon incidental finding in patients undergoing testicular ultrasonography, and grading of CTM plays no role in the prevalence of testicular cancer. Copyright (C) 2008 S. Karger AG, Basel.