In the study we develop and test a novel theoretical framework that examine how innovation speed in technology start-ups are influenced by the uncertain character of the technologies and markets that underlie patented inventions. We rely in our framework on previous conceptual and empirical work to distinguish between perceived state, effect and response uncertainty and to hypothesize about their potential differential impact on innovation speed. In addition, our framework also seeks to explain how the ability of the technology entrepreneur to spot and seize new business opportunities influences the uncertainty-speed relationship in start-up settings. We tested our framework and hypotheses on a unique and comprehensive dataset with detailed information about patented inventions commercialized in start-ups by independent technology entrepreneurs in Sweden. Overall, our results show the value and importance of distinguishing between different kinds of perceived uncertainty when theorizing about the process of developing and commercializing patented inventions in new technology start-ups. Moreover, our empirical findings suggest that the ability to spot and seize new business opportunities can be both an asset and a liability in this process.