Preliminary experiments suggesting the feasibility of using a resonance fluorescence scheme to detect ambient concentrations of OH in the atmosphere (106molecules/cm3) were carried out using OH concentrations near 1012molecules/cm3. TheP1(1)line of thev= 0 → 1 branch of the lowest electronic transition of OH at 2822 Å was resonantly excited with radiation from a doubled dye laser. The subsequent fluorescence from thev= 0 → 0 branch with &Dgr;&ngr; ≅ 3050 cm−1was observed to have a fluorescence efficiency of 0.6 × 10−3in N2at atmospheric pressure with a 10‐mm partial pressure of H2O. This fluorescence occurs 500 cm−1away from any strong Raman line in the atmosphere.