The Kéromnès et al. (2013) mechanism for hydrogen combustion has been optimized using a large set of indirect experimental data, consisting of ignition measurements in shock tubes (566 datapoints in 43 datasets) and rapid compression machines (219/19), and flame velocity measurements (364/59), covering wide ranges of temperature (800 K–2300 K), pressure (0.1 bar–65 bar) and equivalence ratio (φ = 0.2–5.0). According to the sensitivity analysis carried out at each experimental datapoint, 30 Arrhenius parameters and 3 third body collision efficiency parameters of 11 elementary reactions could be optimized using these experimental data. 1749 directly measured rate coefficient values in 56 datasets belonging to the 11 reaction steps were also utilized. Prior uncertainty ranges of the rate coefficients were determined from literature data. Mechanism optimization has led to a new hydrogen combustion mechanism, a set of newly recommended rate parameters with their covariance matrix, and temperature-dependent posterior uncertainty ranges of the rate coefficients. The optimized mechanism generated here was tested together with 13 recent hydrogen combustion mechanisms and proved to be the best one.