This study evaluated the causal effect of environmental friendly activities and resultant environmental performance of enterprises on their organizational performance. More importantly, it analyzed and empirically investigated the mediation of environmental performance in the research model which has been paid no attention to in previous studies. The final research data was gathered from 399 publicly listed enterprisesin in the three main stock markets of Vietnam. Multiple regression analyses were applied to test the causal hypotheses, while mediating procedures were employed to test statistical significance for the mediation mechanism. The empirical findings reveal positive influences of environmental responsibility on organizational and environmental performance that in turn puts a positive influence on organizational performance. Environmental performance is discovered as an entirely mediating factor in the joint research model, where environmental responsibility has no direct effect on organizational performance, but only has indirect effect through environmental performance. When included into the research model, environmental performance will transmit the whole of direct effect of environmental responsibility on organizational performance.