We report the observation of Shubnikov-de Haas oscillations in single crystals of the Rashba spin-splitting compound BiTeI, from both longitudinal [R-xx(B)] and Hall [R-xy(B)] magnetoresistance. Under magnetic fields up to 65 T, we resolved unambiguously only one frequency F = 284.3 +/- 1.3 T, corresponding to a Fermi momentum k(F) = 0.093 +/- 0.002 angstrom(-1). The amplitude of oscillations is strongly suppressed by a tilting magnetic field, suggesting a highly two-dimensional Fermi surface. Combining with optical spectroscopy, we show that quantum oscillations may be consistent with a bulk conduction band having a Rashba splitting momentum k(R) = 0.046 +/- 0.0005 angstrom(-1). DOI: 10.1103/PhysRevB.87.041104