Aberrant DNA methylation of cell-free circulating DNA (cfDNA) has recently gained attention for its use as biomarker in cancer diagnosis, prognosis, and prediction of therapeutic response. Quantification of cfDNA methylation levels requires methods with high sensitivity and specificity due to low amounts of cfDNA available in plasma, high degradation of cfDNA, and/or contamination with genomic DNA. To date, several approaches for measuring cfDNA methylation have been established, including quantitative methylation-specific PCR (qMSP), which represents a simple, fast, and cost-effective technique that can be easily implemented into clinical practice. In this chapter, we provide a detailed protocol for SYBR Green qMSP analysis which is currently used in our laboratory for cfDNA methylation detection. Useful information regarding successful qMSP primers design are also provided.