Measurements were made on the number of fibers per unit cross-sectional area in steel fiber reinforced concrete specimens incorporating various volume fractions of fibers of different types. Based on statistical evaluation of the measured values, the differences in fiber concentrations at different locations on the cross section were assessed. Theoretical expressions were derived for the number of fibers per unit cross-sectional area in fiber reinforced concrete, with due consideration given to the effects of the surrounding boundaries. The effects of vibration on reorientation of steel fibers in concrete were investigated through comparisons betwen the computed and measured values of number of fibers per unit cross-sectional area.