Abstract
This research aims to identify the effect of supply chain flexibility (sourcing flexibility, operating system flexibility, distribution flexibility and information system flexibility) on supply chain performance in the presence of environmental uncertainty in a number of Egyptian industrial private sector operating in governorate Alexandria, in several industries such as chemical industry, food industry, in order to reach this goal, the researcher has developed eight hypotheses, and depend on a survey modified by the researcher to collect preliminary data that meet the purpose of research. The reliability of the research measures was ensured using Cronbach's Alpha test and by means of factor analysis, the researcher confirmed the convergent validity of measurements of research variables. Mediator regression analysis was used through applying the program PROCESS procedure for SPSS Release 2.13.1 to test the hypotheses of the research. the research has found a significant positive effect for sourcing flexibility, operating system flexibility, distribution flexibility and information system flexibility on supply chain performance. Besides, the research revealed that environmental uncertainty is a full mediator between sourcing flexibility and supply chain performance. Conversely, environmental uncertainty acts as a partial mediator between both (operating system flexibility, distribution flexibility and information system flexibility) and supply chain performance.