This paper examilles the effect of inter-industrial network on the competitive outcome of Korean firms between 1981 and 1999. We look for a way to integrate structUral hole theory of market and organizational ecology in explaining the competition among firms for survival and growth. Especially the concept of niche, central to ecological theory, can be measured using the idea that structural autonomy of industry in input-output network determines the industry's niche width. Combilling data from inpur-output table and establishment census between 1981 and 1999, we test two hypotheses that organizations in highly autonomous industry should show lower mortality rates and higher growth rates, and that the competitive effect of density should be lower under the condition of high autonomy in input-output network. Overall, the results from event history analysis for mortality rates and pooled-time series analysis for growth rates confirm our hypotheses.