Seed accelerators are a new generation of business incubators. While the number of seed accelerators worldwide has grown exponentially, there is as yet no consensus on how to measure and analyse their performance. Therefore, the present study, using two pioneering surveys, aims to cast new light on this field by empirically assessing the performance of accelerators and the prospects of their accelerated firms. A model is built on two perspectives that are used to assess the prospects of the accelerated firms: (1) the accelerator´s perspective, and (2) the accelerated start-ups’ perspective. The results confirmed, at statistically significant levels, that the portfolio size of accelerators, their start-ups´ survival rates, and the number of employees in the accelerated firms, have a positive effect on the median value of the funding received by the accelerated start-ups from the accelerators’ funds. Furthermore, accelerators located in the U.S., and those with the greatest longevity, are shown to have a higher impact on start-ups´ survival rates. The study is not free of limitations, but its findings contribute to the still scarce quantitative literature on the performance of accelerators, and provide important managerial implications for their managers, investors, and entrepreneurs.