This paper presents an implementation of Lean Manufacturing techniques combined with inventory management in an SME company dedicated to the commercialization and elaboration of marble and granite pieces, this to reduce the inventory and scrap of marble and granite that is generated throughout the production process. A common problem in SMEs in this area is the high level of inventory and excess scraps dye to the lack of supply planning, a deficient inventory and warehouse process, as well as improper material handling. There is previous research that addresses the problem of excess scraps and a high inventory level separately, so the contribution of this article consists in addressing both problems in this Little-studied sector. For this, a model is proposed integrating the Lean Manufacturing tools: 5's and Kaizen Standardization with those of Planning and inventory Management. The model is validated through a pilot, from which inventory and scraps were reduced by 10%. Also, the sheets reuse percentage increased to 60.70%, inventory turnover increased from 0.67 to 0.75, and inventory accuracy rate improved from 88% to 95%.