This paper investigates the determinants of firms’ innovative performance, by exploring the effects of different innovation strategies related to generation and acquisition of technological knowledge. The analysis is based on a sample of 1329 Spanish manufacturing firms. The results suggest that R&D contracting has not significant effect on firms’ innovative performance and that cooperation with external agents has a limited effect. In contrast, the development of in-house R&D activities seems to be the most important strategy to introduce new products onto the market. These results warns against the risk of overrating external knowledge sourcing, and highlight the need for policy makers to establish innovation policies mainly focus on strengthening the technological capabilities of firms.Este artículo examina los determinantes del desempeño innovador de las empresas manufactureras españolas, considerando especialmente el efecto que ejercen diferentes estrategias relacionadas con la generación y adquisición de conocimiento. El análisis es realizado sobre una muestra de 1329 empresas activas en innovación. Los resultados indican que la contratación de actividades de I+D no influye sobre el desempeño innovador de las empresas y que la cooperación con agentes externos tiene un efecto limitado. En contraste, el desarrollo de actividades internas de I+D se muestra como la principal estrategia para la introducción de productos nuevos en el mercado. Estos resultados constituyen una llamada de atención para no sobrevalorar la importancia de la adquisición externa de conocimiento y destacan la necesidad de diseñar políticas de innovación centradas fundamentalmente en el fortalecimiento de las capacidades internas de las empresas.This paper investigates the determinants of firms’ innovative performance, by exploring the effects of different innovation strategies related to generation and acquisition of technological knowledge. The analysis is based on a sample of 1329 Spanish manufacturing firms. The results suggest that R&D contracting has not significant effect on firms’ innovative performance and that cooperation with external agents has a limited effect. In contrast, the development of in-house R&D activities seems to be the most important strategy to introduce new products onto the market. These results warns against the risk of overrating external knowledge sourcing, and highlight the need for policy makers to establish innovation policies mainly focus on strengthening the technological capabilities of firms.