We exploit increased access to detailed employer-employee data to assess whether outside board members affect innovation performance among start-up firms. Using data for all new limited companies in Sweden born during 1999–2013 which have no more then 10 employees when formed, we provide structural equation estimates that deal with the endogenous selection of board directors. Our empirical findings show that an increase in the board’s expertise, measured by the relative productivity of the firms where outsiders are employed, has a significant and positive impact on the new firm’s propensity to apply for both patents and trademarks.