Collagen methylation has been exploited in various applications involving living cells. We have observed correlation between the collagen methylation with the rate of cell 1 proliferation in three-dimensional (3-D) microenvironment. To quantify the degree of collagen methylation, we have developed a capillary zone electrophoresis method. Ltd Using a polyvinyl alcohol-coated fused-silica capillary and UV detection at 200 nm, we have optimized pH and separated the native collagen into three major bands in phosphate buffer (50 mm, pH 2.5) with 0.05% hydroxypropylmethylcellulose. Under these conditions, the methylated collagens were separated into four major bands, which changed with different methylation reaction conditions. We propose an index to quantify the degree of collagen methylation that also correlates with their effects on cell proliferation.