The objective of the study is to understand the correlation between inter-firm cooperation and firm technical efficiency. It based on the background of the difficulties and limited production resources faced by micro and small industry (MSI) that impede them to move towards production frontier that makes firm less efficient technically. Therefore, this study will discuss whether cooperation conducted by MSI will bring improved technical efficiency. Estimation is taken by using maximum likelihood method on firm production function stochastically. Using data from micro and Small Industry Survey Year.. 2004 published by National Bureau of Statistic of Indonesia, inter-firm cooperation is measured through index with Principal Component Analysis which reflects the degree of the cooperation. As the first study in Indonesia for the topic, result shows a positive correlation between inter-firm cooperation and technical efficiency in micro industry, otherwise the correlation is not found in small industry. This indicate that inter-firm cooperation is not "panacea" to attain technical efficiency, yet it is depending on the size the firm.