  We report the observation of Shubnikov-de Haas (SdH) 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 field up
to 65 T, we resolved unambiguously only one frequency $F = 284.3\pm 1.3$ T,
corresponding to a Fermi momentum $k_{F} = 0.093\pm 0.002$\AA$^{-1}$.The
amplitude of oscillations is strongly suppressed by 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 $k_{R}=0.046\pm$\AA$^{-1}$.
