Analytical solutions for steady-periodic ground-coupled heat conduction problems for cylindrical and three-dimensional rectangular slab-on-grade floors beneath refrigerated structures with uniform and partial insulation are presented in this paper. The solutions provide the soil temperature field, and the total slab heat gain. A parametric analysis is conducted to determine the effect of thermal insulation U-value and insulation width on the mean, amplitude, and phase lag of total slab heat gain. In particular, it was found that the mean and the amplitude of the total slab heat gain are effectively independent of its shape but are strongly affected by the slab size and thermal characteristics. [S0199-6231(00)00502-5].