Objective: Screening of kidney diseases by urinalysis in school children has been approved in many parts of the world with inexpensive tools such as urinary dipsticks. In this study, we investigated the prevalence of hematuria in a large sample of 6 to 15-year-old school students in Makkah and Baha, Saudi Arabia. Design: A total population of 12,347 students in primary and middle schools in Makkah and Baha, Saudi Arabia, were investigated for hematuria during 2007. There were 7,299 students in Makkah (5,007 boys and 2,292 girls) and the remaining 5,048 were in Baha (2,734 boys and 2,314 girls), aged from 6 to 15 years old. All the studied children were apparently healthy and asymptomatic. Parents' consents were taken prior to the test. A random fresh mid-stream urine was collected to complete the urine analysis (by dipstick and microscopy) to detect microscopic hematuria, albuminuria or pus cells. Measurements of the height and weight were also done and blood pressure was measured for each student. Results: Among the 12,347 students screened and urine samples provided, 2,745 (22.23%) had hematuria, 1,822 (14.76% of the total population) from Makkah and 923 (7.48%) from Baha. Analysis of the prevalence of hematuria in students in Makkah and Baha showed that there was a very highly significant difference between the two cities (P value = 0.0000). There were 842 students (7% of the total population) had positive hematuria and hypertension and 2,678 students (22%) had negative hematuria and hypertension with a highly statistically significant difference between positive hematuria students and negative students in the prevalence of hypertension (P value = 0.0044). Conclusion: Asymptomatic hematuria might be detected by the school screening program and should be considered as an inexpensive way for early management of some renal diseases.