Using cokriging, estimates and estimation variances of the gravimetric moisture content (GMC) were made using one and two additional random functions: the bare soil surface temperature and the percent sand content. Various measures of the differences and quality of the estimates for kriging and cokriging were calculated and compared on the basis of the sample correlation and whether the auxiliary random functions were over-sampled with respect to the GMC. The average estimation variance for cokriging compared to kriging was reduced for all levels of absolute sample correlation considered (i.e., 0.15-0.83). It was found that the additional complexity of cokriging may be justified when the magnitude of the sample correlation exceeded 0.5 and the auxiliary functions were over-sampled with respect to the GMC. (Copyright (c) Soil Science of America Journal, January-February, 1987.)