The characteristics of a liquid sheet formed by the impingement of two round liquid jets are analyzed theoretically. Since the velocity profile of the impinging jet greatly affects the sheet characteristics, the sheet characteristics are analyzed using round impinging jets with uniform or parabolic velocity profiles. The calculated sheet shape is compared with the results of theoretical analyses reported in previous studies. The effects of the velocity profile of impinging jets on the sheet characteristics are shown theoretically. Experiments are conducted in order to verify the theoretical analysis using short and long nozzles. The sheet contour is determined by two mechanisms, i.e., the force balance at the periphery between the liquid inertia and the surface tension, and the unstable wave growth. A critical condition in which the sheet disintegrates as a result of the unstable wave growth is newly proposed. The predicted sheet shapes agree somewhat with the results of experiments using short and long nozzles. The predicted sheet breakup lengths calculated using the newly proposed critical condition agree well with the results of these experiments. The predicted sheet velocity distributions exhibit slightly smaller values compared with measurements reported in previous studies. (C) 2014 Elsevier Ltd. All rights reserved.