High powered light emitting diodes (LED) are investigated for possible uses as light sources in flow diagnostics, in particular, as an alternative to laser-based illumination in particle imaging flow velocimetry. Recent developments in solid state illumination resulted in mass-produced LEDs that provide average radiant power in excess of 10 Watt. By operating these LEDs with short duration, pulsed currents that are considerably beyond their continuous current damage threshold, light pulses can be generated that are sufficient to the illuminate and image micron sized particles in flow velocimetry. Kilohertz frame rate PIV measurements in water are presented. The feasibility of LED-based PIV measurements in air is also demonstrated.