The DNA/histone ratio was calculated through Feulgen/fast green absorption in different regions of polytene chromosomes inPhaseolus coccineusembryo suspensor cells. A great variability of ratios, related with the structural characteristics of DNA in the different regions, has been found. This seems to indicate that complexes of histone with DNA may depend on changes in DNA metabolic activity. In one and the same cell, and even in one and the same chromosome, different chromosome segments have different DNA/histone ratios.