ATTO Rho6G is a new rhodamine dye, based on the well-known laser dye Rhodamine 6G. Characteristic features of the label are strong absorption, extraordinarily high fluorescence quantum yield, and high thermal and photo-stability. The dye is moderately hydrophilic. After coupling to a substrate ATTO Rho6G carries a net electric charge of +1. The fluorescence is excited efficiently in the range 515 - 545 nm. A suitable excitation source for ATTO Rho6G is the 532 nm line of the frequency-doubled Nd:YAG laser.