Craig, Geffen and Morse (CGM) Method, one of the most thorough and practical prediction method for waterflooding prediction, was applied to the Palogrande-Cebu Field in Colombia South America to define the vertical distribution of the injected water of a project that has 18 years old. The field has five producing units that had been waterflooded since 1984. The CGM method was adapted to match the actual fluid production rendered confident vertical water distributions and actual water saturation for the different units and for all the producing wells. Methodology was as follows: Analysis of the injection and production curves. For every production well a rigorous analysis of the production curves was compared with the injection curves of the closest injectors. This analysis allowed a selection of the injectors that affected the fluid production of the well in analysis. This step gave a qualitative approach.Injectivity analysis. Logs of water injection distribution were analyzed for all the injectors. This step gave a vertical injection distribution for the five units at the injector but did not give a clue about the areal distribution of the water.CGM method. The CGM was adapted to be able to match the actual fluid production of the field. For each producer, the selected injectors in step 1 were evaluated. Some times it was necessary to include or reject injector wells to get the match of the produced fluids.The combination of the three steps allowed getting a real view of the areal and vertical water distribution. The above method is been used to get a realistic numerical simulation of the field, since a thorough knowledge of the field has been reached. This paper describes in detail the methodology and the field results for Palogrande-Cebu field.