The process includes the steps of (i) dissolving finasteride in a substantially anhydrous organic solvent selected among n-butyl acetate, iso-butyl acetate, sec-butyl acetate, tert-butyl acetate, C5 alkyl acetate and mixtures thereof, at a temperature equal to or lower than the boiling point of said organic solvent; (ii) slowly cooling said finasteride solution to a cooling temperature determined on the basis of the chosen solvent; (iii) maintaining the resulting suspension at the cooling temperature for a period of time equal to or less than 16 hours; and (iv) recovering the resulting solid phase containing Form I of finasteride, for example by means of filtration, and removing the solvent, for example by means of drying said crystals. The process allows for obtaining the Form I of finasteride only and in a pure form.