We present a new common path configuration Fourier domain low coherence interferometry (fLCI) optical system and demonstrate its capabilities by presenting results which determine the size of cell nuclei in a monolayer of T84 epithelial cells. The optical system uses a white light source in a modified Michelson interferometer and a spectrograph for detection of the mixed signal and reference fields. Depth resolution is obtained from the Fourier transform of the measured spectrum which provides the axial spatial cross-correlation between the signal and reference fields. The spectral dependence of scattering by the samples is determined by windowing the spectrum to measure the scattering amplitude as a function of wavenumber. We present evidence that fLCI accurately measures the longitudinal profile of cell nuclei rather than the transverse profile.