In recent years new observational data of pre-main sequence stars (pre-MS) with metallicity lower than solar have been made available; the study of the star formation regions requires comparison between theoretical models and observational data to assign masses and ages to the stars. However, the calculations of pre-MS models, mainly for low and very low masses, are particularly challenging because they require an accurate treatment of the microphysics associated with relatively cold matter. We present a large database of pre-MS tracks and isochrones for a wide range of chemical compositions (Z = 0.0002/0.03), masses (M=0.2/6.0M_sun) and ages (1/100 Myr) for a solar calibrated mixing length parameter, alpha =1.9. For each chemical composition additional models have been computed with alpha =1.5, and with two different initial deuterium abundances. Models are computed with a standard stellar evolutionary code adopting the most recent physical ingredients.