Experimental measurements were made on the scattering of polarized light to determine all six independent elements of the Mueller matrix for three types of casein foams with different bubble size distributions. These elements were correlated with the liquid fraction and the bubble size distribution which were measured independently during free foam drainage by multiple linear regression analysis. A correlation between M-11 and M-22 and the liquid fraction and the bubble size distribution with a high correlation coefficient has been obtained. M-12 shows dependence only on the bubble size distribution but not on the liquid fraction. M-33 is associated with both parameters. For initially monodispersed casein foams, M-34 is almost independent of the liquid fraction and the bubble size distribution, whereas M-44 is significantly correlated with the mean bubble diameter. For the bidispersed casein foam, both M-34 and M-44 are mainly associated with the liquid fraction.