The construction industry is deemed to be one of the most flourishing industries in Egypt. It greatly contributes to the national GDP and represents one of the leading sectors in the Egyptian economy recorded at a reasonable growth rate recently. Throughout the history of work in mega projects, particularly in the petroleum, chemical industries and power plants, it has been noticed that erroneous technical, managerial and ethical behaviour of personnel is dominant in the Egyptian work environment, which to a great extent affect passively the performance indices and success of the construction projects. Therefore, the aim of this research work is to introduce a model that describes the influence of ethical aspects on a number of selected performance indices used to measure the success of construction projects in Egypt. To this end, questionnaire surveys and interviews were used as data collection means. The questionnaire contained 185 questions covering 24 independent variables. The independent variables were selected to cover a number of critical technical, managerial and ethical issues that take place during the subsequent stages of large construction projects. In this research, only results concerning the influence of ethical aspects are presented. A number of statistical analysis tools were presented, using non-parametric analysis techniques and a number of regression models were developed to evaluate the project performance During both the planning and implementation phases. The study has detected three dependent performance indices that have been correlated with three ethical independent aspects.