Performance measurement of start-ups is an emerging field of research. Relative efficiencies of thirty-nine Indian start-ups that became unicorns in the year 2022 were assessed using the DEA slack-based model. The inputs used in the DEA model consisted of human, financial, and technological capital indicators, while the output indicators were primarily financial parameters. Eight Decision Making Units achieved relative efficiency of 1 and 13 DMUs displayed efficiency of more than 50%. The results indicate that start-ups in India are operating at a lower efficiency. The performance of unicorns in India has been studied for the first time in this paper. The study is original in terms of indicators used in the DEA model to predict start-up performance and the application of slack-based DEA model for analyzing start-up efficiency.