OBJECTIVE: To determine the relative amounts of RNA and DNA from adipocytes and adipose stromal-vascular cells to better assess differential gene expression for estrogen receptor and cytochrome P450 aromatase in the two cell fractions of adipose tissue. STUDY DESIGN: Colorimetric and fluorometric assays were used to measure total RNA and DNA, and the relative cell numbers as well as the relative contribution of RNA from adipocytes and stromal-vascular cells were assessed. RESULTS: Adipocytes and stromal-vascular cells exist in a ratio of 2/1. RNA/DNA ratios are the same in the two cell fractions. CONCLUSION: In human subcutaneous adipose tissue, adipocytes are twice as numerous as stromal-vascular cells. The overall transcriptional activity of the cell types appears similar.