The calcium palmitate monolayer formed from palmitic acid on calcium-containing substrate can be examined regarding the study of hydration by applying the quartz crystal microbalance (QCM) technique. Monolayers of calcium palmitate were deposited on piezoelectric crystal plate by the Langmuir-Blodgett (LB) technique. Analysis of complete conversion to calcium palmitate was performed by identification of its infrared spectra. The estimation of the hydration for the multilayered calcium palmitate is compared with the data of the multilayered calcium stearate in the literature. The QCM measurement for determining hydration number is based on the results of McCaffrey, particularly employed in the treatment of drying in vacuum (R.R. McCaffrey, S. Bruckenstein, P.N. Prasad, Langmuir 2 (1986) 228). In our experiments, the frequency change of the oscillating quartz transducer for the skimmed calcium palmitate also increased after drying in vacuum. Hydration behavior of the multilayered calcium palmitate LB film is discussed, and it was shown that the hydration of calcium palmitate exists as monohydrate, though its hydrophobicity is relatively a little low compared with that of calcium stearate, which has a longer hydrocarbon chain length.