Temperature is the most important factor in regulating the germination of nondormant seeds at the beginning of the growth season. The present study was conducted to produce simple regression models to predict how temperature affects the time it takes for 50% of a selection of flax seeds to germinate. R-square (r(2)) values of regression coefficients of the equations established for flax cultivars varied from 0.899 (Antares) to 0.886 (Bionda). The optimum temperature for the time to germination for both cultivars was calculated using the coefficients obtained from the regression models. The optimum temperatures were found to be between 22.10 and 22.05 degrees C for Antares and Bionda, respectively.