We have constructed a steady-state radially-resolved diffuse reflectance spectrometer capable of simultaneously measuring the absorption (μa) and transport scattering (μs') spectra of tissue-simulating phantoms within an adjustable 160 nm wavelength interval. We present absorption and transport scattering spectra of various tissue-simulating phantoms reconstructed from diffuse reflectance measurements. When compared with the known optical properties of the phantoms, the returned optical coefficients are generally found to be accurate to within 10% for media in which the diffusion model of photon transport is relevant. In addition, Monte Carlo simulations are presented which illustrate the dependence of the errors in the returned optical properties on the source-detector separation distances used in the measurement. Finally, we discuss determinations of hemoglobin oxygen saturation derived from diffuse reflectance measurements of tissue-simulating phantoms.