Dynamic behaviors of axisymmetric and planar opposed jets have been experimentally studied at 786 < Re < 6288. The flow patterns were investigated by a smoke-wire technique, and the smoke-wire photos were recorded by a high-speed camera. Different flow regimes of axisymmetric and planar opposed jets have been identified. Axisymmetric opposed jets exhibit axial quasi-periodic oscillations, stagnation point offsets, and steady states, while planar opposed jets exhibit both horizontal instabilities and deflecting oscillations. Effects of the nozzle separation and the exit Reynolds number on the dynamic characteristics of axisymmetric and planar opposed jets have been investigated and discussed. Maps of parameter spaces describing the flow regimes of axisymmetric and planar opposed jets at various nozzle separations and exit Reynolds numbers have been presented. (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 1434-1445, 2011