This paper results from the findings of the research conducted during my PhD. The dissertation had as issue the teachers who are involved in Health Education and/or Sexual Education projects in Greek Schools. One of the key results relates to inadequate or non-existent education / training of teachers in the planning and implementation of projects in general. The finding is that the programs are implemented in an improvised manner or random and in any case with a low efficiency. As a result of previous findings, in this text we aim to present and analyze a design tool and implementation of educational programs, the "logic model", which could contribute to improving of the previous failure. This is a model internationally recognized and highly used that could help active teachers to better programming, implementing and evaluating projects within their school unit.