Geographic Information Systems and open source software are becoming more and more popular resulting in an increased requirement for data migration from common non spatial software to spatially referenced software. MySQL is a very popular open source Database Management System used by most web developers but without support for spatial referencing. PostgreSQL is an open source software that supports Geographic Information Systems. It is often necessary to migrate data from MySQL to PostgreSQL and it is possible to identify many tools that are capable of executing the desired task. Therefore best available tool should be selected to ensure that the selected tool satisfies the main functionalities expected of the software and capabilities of performing the tasks with user friendly features. This paper describes a systematic methodology adopted to select the best free tool for data migration from MySQL to PostgreSQL using literature and rational judgement incorporating a qualitative ranking system to Migrate the base data. For easy comparison, an Evaluation Score of Tool was defined by calculating the percentage of available functionality when compared with the user desires for satisfaction. After comparing three available tools, Postgres Plus 8.3 free software was identified as the best with a Evaluation Score of Tool value of 76%. The present work identified 3 main and 11 sub database functions together with 4 main and 13 sub components of Graphical User Interface functionality as important parameters for data migration.