Th e paper complements a new line of research that includes the fi rm heterogeneity in trade models. Th e central idea of this research is that only the largest and most effi cient fi rms are capable of exporting. However, the empirical evidence has confi rmed that a large number of SMEs is also involved in internationalisation. Given this context, the aim of the paper is to analyse the infl uence of collaborative networks between fi rms and institutions as an alternative mechanism to the small size of the majority of the fi rms in the agri-food industry. To this end, there was used a longitudinal panel between 1994 and 2012 comprising a sample of 342 Spanish fi rms involved in the business sectors of the food, meat, drink and tobacco industries, and a dynamic Heckman-Probit model was implemented. Th e fi rst stage studies the positive infl uence of collaborative networks in fi rms' decision to export and the second stage analyses the eff ect of cooperation mechanisms on export intensity. Th e results show a positive eff ect of business cooperation networks in both stages suggesting that SMEs can overcome the barrier of their small size in their internationalisation process through other mechanisms, such as collaborative networks.