The launch of the first product is an important event for start-ups, because it takes the new venture closer to growth, profitability and financial independence. However, entrepreneurship literature lacks theory and data on new product development and innovation speed. Integrating insights form new product development literature with resource-based theory, we construct a conceptual framework concerning the antecedents of innovation speed in start-ups. In particular, we argue that pre-founding R&D efforts and intangible assets such as team tenure, experience of founders, and collaborations with third parties are important for innovation speed. We collected a unique dataset on 99 research-based start-ups (RBSUs) and use an event-history approach to test our model. We find that RBSUs differ significantly in their starting conditions and that these differences have a significant effect on the time it takes to launch the first product. The impact of starting conditions on innovation speed differs however between software, medical-related, telecom and other technologies. Although intuition suggests that start-ups that are further in the product development cycle at founding launch their first product faster, we find that software firms starting with a beta-version experience slower product launch. Next, it is shown that team tenure and experience of founders leads to faster product launch. Contrary to expectations, alliances with other firms do not significantly affect innovation speed and collaborations with universities lead to longer development times. The insights of this study enhance our understanding of product development processes in start-ups and the differences between slow growers and fast growers. Keywords: Intangible assets, New Product Development and Start-Ups