Understanding obstacles in front of communication system has turned into a critical task executed by managers. Present study analyzes major vulnerabilities to organizational communication from structural, behavioral and contextual aspects. The statistical population includes employees and managers in the headquarters of National Iranian Oil Company. After assessing the validity and reliability of a conceptual model, we used Kolmogorov–Smirnov test, T-test and F-test for analyzing our data. The results show that priority of communication barriers are as follows: structural elements like centrality and formality. Contextual elements like cultural and technical barriers and finally behavioral elements like perceptual and human barriers.