A versao Portuguesa deste artigo pode ser encontrada em http://ssrn.com/abstract=2179234 As alteracoes dos mercados e a intensificacao da competicao requerem novas formas de cooperacao empresarial. As estrategias relacionais que tem como pilar a confianca, permitem as empresas criar condicoes ao desenvolvimento da cooperacao, contribuindo para o aumento da competitividade empresarial. O estudo que aqui se apresenta visa averiguar o impacto da cooperacao e da coopeticao, associadas ao ambiente concorrencial e a confianca, na performance empresarial. Para o efeito, atraves de um estudo empirico de caracteristicas transversais, baseado numa amostra de 92 empresas industriais portuguesas, utilizando a analise factorial exploratoria e a analise de regressao linear simples e multipla constatou-se que as relacoes de cooperacao e de coopeticao, aliadas ao ambiente concorrencial e ao controlo formal, tem um efeito positivo na performance. Assim, as alteracoes do funcionamento dos mercados, tendencialmente mais globalizados, requerem que as empresas recorram mais a estrategias relacionais e encarem tambem os concorrentes como parceiros de negocio. The Portuguese version of this paper can be found at http://ssrn.com/abstract=2179234 Markets changes and competition enhancement require new and different forms of corporate cooperation. Relational strategies based on trust as fundamental pillar allows firms to create the conditions for cooperation development, contributing to increase business competitiveness. The goal for the present investigation Is to seek the impact of both cooperation and coopetition, together with competitive environment and trust, on business performance. Seeking this goal, a sample of 92 Portuguese industrial firms was used in an empirical transversal characteristics study, using an exploratory factor analysis, together with simple and multiple linear regression analysis. This research shows that cooperative and coopetitive relationships when crossed with competitive environment and formal control mechanisms have a positive effect on business performance. Thus, changes on markets functioning, in growing globalization, demand for wider relational strategies between firms and face the competitors also business partners.