Abstract: In this research, the possibility of prediction of days to germination of seeds for Flue-cured and Oriental tobacco (Nicotiana tabacum L.) by mathematical models based on temperature was investigated. A model, (D = α - (bxT)+(cxT2) was used that previously predicted the time to emergence in relation to temperature for some vegetable crops and was unchanged when applied to both tobaccos. It was found that the new mathematical models obtained after adapting the present data to the above mentioned model could be used safely in terms of the studied parameter. In addition to determining optimum (T0 = -b / 2xc) seed germination temperature, days to germination was calculated by using coefficients obtained from the regression models. Considering the marked interest by many researchers in modeling plant growth and development in recent years, the equations produced in this study may be helpful in this field. Models which predict days to germination or optimum temperatures could be used for adjusting a proper time for seed sowing according to different regions and utilizing the growing season of these regions more productively.