Telomere shortening is an important risk factor for cancer and accelerated aging. However, it is becoming evident that oxidatively damaged DNA within the telomere sequence may also cause telomere dysfunction. Here we describe a reliable, cost-effective quantitative PCR (qPCR)-based method to measure the amount of oxidized residues within telomeric DNA that are recognized and excised by formamidopyridine DNA glycosylase (FPG). We also report that in an in vitro model of oxidative stress oxidized base lesions measured using this method are more prevalent within telomeric sequences. Furthermore, this method is sufficiently sensitive to detect changes in oxidative stress induced by zinc deficiency and hydrogen peroxide within the physiological range.