Systematic measurements are reported of OH chemiluminescence from a premixed laminar ¯ame at pressures and equivalence ratios ranging from 0.5 to 2.5 MPa and 0.66 to 0.86, respectively. The objective was to obtain non-existent experimental data and to determine the viability of using OH chemiluminescence as an active-control parameter for high-pressure, premixed ¯ames. The signal from the ®rst electronically excited state of OH to ground (at 305.4 nm) was detected through a band-pass ®lter with a photo-multiplier tube. For constant mass ¯ow rate, OH emission decreased signi®cantly with increasing pressure. Emission also monotonically increased with the equivalence ratio. A linear relationship was observed between increasing mass ¯ow and increasing chemiluminescence. These trends support the conclusion that suitable resolution and dynamic range exist for a high-pressure ¯ame to be adequately controlled to minimize both NO x and CO emissions. Results are presented for a simple, active-control system using OH chemiluminescence measurements to demonstrate ¯ame stabilization for equivalence ratio disturbances at ®xed, elevated pressures. Finally, only qualitative agreement was observed between the measurements and numerical predictions of OH chemiluminescence using an adiabatic, freely propagating premixed ¯ame. Although more work is required on the chemical-kinetic mechanism of OH chemiluminescence, the modeling effort supports the use of OH chemiluminescence for active-feedback-control applications.