Searching for the most rewarding sources of innovative ideas remains a key challenge in management of technological innovation. Yet, little is known about which combinations of internal and external knowledge sources are triggers for innovation. Extending theories about searching for innovation, we examine the effectiveness of different combinations of knowledge sources for achieving innovative performance. We suggest that combinations involving integrative search strategies – combining internal and external knowledge – are the most likely to generate product and process innovation. In this context, we present the idea that cognitively distant knowledge sources are helpful for innovation only when used in conjunction with knowledge sources that are closer to the focal firm. We also find important differences between product and process innovation, with the former associated with broader searches than the latter. Using a large-scale pooled sample of UK firms, we find overall support for our conjectures, particularly in terms of product innovation.