The relations between the indices of light attenuation and backscattering in the upper 300-meter water layer of Lake Baikal are presented. The data were obtained during measurements of the depth profiles of hydro-optical characteristics in different water areas of the Lake in March and August, 2003. The obtained relations are compared with the available results for the ocean and sea waters. A certain ambiguity of dependences for the regions with maximal (more than 1.2 m-1) attenuation index is found.