The instantaneous two dimensional velocity fields around the intake valve of an internal combustion engine were experimentally investigated by means of particle image velocimetry. The measurements were taken in a plane perpendicular to a cylinder head near the intake valve in a simulated engine setup using a diesel engine cylinder head and an acrylic cylinder with glass optical windows. The intake valves were actuated by a motor driven cam. The measurements at various cam rotating speeds and valve lifts were made to investigate the unsteady effects of the intake valve flow. For comparison of dynamic and static valve flows, measurements with stationary valves were also conducted.The instantaneous two dimensional flow fields showed a well organized intake jet, and entrainment of the ambient air into the jet. For the same valve lift and pressure drop across the intake valves, the static valve flow showed higher jet velocity than the dynamic intake valve flow. The dynamic intake valve flow showed noticeable cyclic variation in detailed flow patterns, but the overall flow pattern and main jet behaved repeatably in separate flow samples.