Although they are often considered to be more flexible and adaptable than their larger counterparts, small and medium-sized firms now evolve in a rather uncertain environment which may, more than ever, impede their capacity to compete internationally. In this context, and in order for those firms to continuously improve themselves, it is believed that they need to acquire and develop particular capabilities. The objective of this paper is therefore to identify some of the critical capabilities that characterize successful SMEs in industries where significant added value is created. The results presented are drawn from a large research project carried out among manufacturing subcontractors in the aerospace industry in Canada.