A variety of measurements are required in order to investigate combustion characteristics in co-swirling flames. Four different diagnostic techniques are used in this study. A flow visualization technique is used to observe fuel/air mixing patterns in these flames. Laser Doppler Velocimetry is employed to characterize the flowfield in the flame including the size and shape of the recirculation zone and shear layer. A high frequency compensated thermocouple technique is used to measure the temperature field. Gas sampling and analysis are employed downstream of the flame to quantify emissions characteristics. These measurements are necessary in order to characterize co-swirling flames which result from strongly coupled thermal, mass, and momentum transport processes.