The genetic ressource of Nicotiana tabacum L. existing at the Tobacco Research Institute of Cuba is presented. It has 758 N. tabacum accessions and 19 wild species of the Nicotiana genus. Foreign varieties and all the primitive and local materials of the country form this collection. A meticulous work that allowed the qualitative and quantitative characterization of the materials with the use of 40 descriptors was carried out. Multivariate studies, guided to give a bigger exploitation to each genetic source where the tobacco varieties were grouped in subgroups inside the Black, Virginia, Oriental, Burley and Semi-Oriental types were made. A high genetic variability was observed and good results were obtained on seed increase and conservation. The present study revealed variations in the reaction to diseases. 22 resistance accessions to blue mold (Peronospora tabacina), 111 to black shank (Phytophthora parasitica) and 64 to the Tobacco Mosaic Virus were determined. This germplasm bank has served as base for the crop improvement and it has contributed to the preservation of the genetic diversity.