We present and apply a methodol. for the single-shot measurement of abs. concns. of the OH-radical in a turbulent, premixed natural gas/air flame. The method is based on a combination of detailed numerical simulations of the turbulent flame and an exptl. approach using planar laser-induced fluorescence (LIF). The numerical simulation is used to predict LIF intensities. It shows the existence of a sharp correlation between the LIF signal after excitation of the A-X(3,0) P2(8) transition near 248.45 nm and OH concns. for a wide range of conditions, including stationary and instationary laminar flames of different strain rates, with different models to treat mol. transport and different degrees of heat loss. This correlation allows the transformation of measured OH-LIF intensity images into abs. OH concn. maps.