In this research six cyanine fluorophores for the quantification of dsDNA in the pg-ng range, without amplification, are compared under exactly identical conditions: EvaGreen, SYBR Green, PicoGreen, AccuClear, AccuBlue NextGen and YOYO-1. The fluorescence intensity as a function of the amount of dsDNA is measured at the optimal wavelengths for excitation and emission and for each dye the limit of detection and the response linearity at low levels of dsDNA are determined. No linear range was found for SYBR Green and YOYO-1 for pg-ng quantities of dsDNA. EvaGreen, PicoGreen, AccuClear and AccuBlue NextGen show good linearity in the pg-ng range. AccuClear exhibits the widest linear range of 3 pg–200 ng, whereas AccuBlue NextGen turned out to have the highest sensitivity of the tested dyes with a limit of detection of 50 pg.