The purpose of Lean is generating a continuous flow in-process and satisfy customer needs with the lowest resource consumption through the continuous elimination of waste, variations, and inflexibilities. The application of lean in the manufacturing and services sector generates great benefits but few investigations related to the Implementation of this philosophy in Service Organizations. Whereby, in the present Monograph develops a case study in the company payments process in the company Alianza Fiduciaria, describes the diagnosis made, the implementation plan and the results obtained.