In this research, poplar and pine timbers have been dried in heat pump dryer functioning on the basis of 24-h operation. The change in weight in all of the timbers was followed in the drying chamber and drying stopped when the desired weight was achieved. Initial moisture content of the poplar timbers was 1.28kg water/kg dry matter, and the moisture content was reduced to 0.15kg water/kg dry matter moisture content in 70h; the moisture content of the pine timbers, which was 0.60kg water/kg dry matter, was reduced to the same amount in 50h. Drying air temperature, relative humidity, and stack weight were measured and collected during drying and saved on a computer and analyzed afterwards. The moisture ratios were analyzed with Statgraphic computer program by using semitheoretical models and empirical values. Correlation and standard error of estimation (SEE) and R2 values were achieved.