A balloon-borne laser radar (LIDAR) system for the determination of stratospheric hydroxyl radical concentration has been constructed and flown by Goddard Space Flight Center. The system measured hydroxyl in the 34--37 km altitude range throughout an afternoon and early evening yielding the first post-sunset hydroxyl determinations ever obtained. Daytime values (~5¿106 cm-3) were somewhat lower than previous measurements using in situ resonance fluorescence. Nightime values (~7¿105 cm-3 (@ 2100 CDT) were higher than predicted by current one-dimensional (1--D) models. Possible sources of these discrepancies along with improvements possible in future systems are outlined.