Purpose: The purpose of this study was to calculate the added value, thereby identifying the types and modes of failure of prescription filling procedures in the phamacy at the Valle del Lili Clinic-Foundation (FCVL). Methodology: A descriptive study was conducted of each step in the prescription filling procedure inthe pharmacy at the FCVL from december 1, 1999 to december 30, 2003. The study allowed; defining each procedure: identifying the needs of different groups of interest or customers in each process; and documenting and verifying each procedure «as it is». It also included an analysis of each in the process, a definition of value