Lyophilization or freeze-drying of fruits is being carried out experimentally and a mathematical model is proposed and checked using the obtained experimental data. The experiments are being carried out in a commercial freeze-dryer, Labconco Freezone Bulk Tray Dryer model 7806000 and Freezone 6 liter Freeze Dry System model 7753000. Sliced pineapples of uniform thickness are used in the lyophilizer. The initial and final moisture contents are measure by the loss-on-drying (LOD) technique in a laboratory LOD instrument. Moisture removal percents are then correlated to the slice thickness and drying time. A mathematical model, based on a published, simple model, is proposed and used to correlate the experimental results. The model provides a good representation of the experimental trends.