Recent results and used way of tissue optical properties measurements in vitro with laser goniophotometer are presented. The optical properties were obtained on the basis of an indirect technique using solution of the radiative transfer equation, which relate the optical parameters of tissue with the measured parameters of reflected and transmitted radiation. The angular patterns of reflected and transmitted radiation by optically thick saline-soaked samples of tumor tissue, namely, mammary fibroadenoma, were measured at the wavelength of 0.63 μm, and the measurement data were inverted to find the absorption and extinction coefficients and the parameters of the phase function of these tumor samples. Obtained values of the optical parameters have been found to be of the same order of magnitude as the earlier reported data for similar tumor samples.