It is recognized that helical vortices are formed in swirling jet flows and promote mixing in comparison to the jets without swirl. However, influence of these vortices (including precessing vortex core) on stabilization of flames is not completely understood. Developing nowadays volumetric velocimetry techniques can provide deeper insight into this issue. The aim of the present study is to directly investigate 3D vortex structure in an open swirling turbulent jet and premixed methane-air flame by using a tomographic PIV system.