An experimental investigation of the Richtmyer–Meshkov instability is carried out in a shock tube. The purpose of this study is to obtain information on the growth in the thickness of the turbulent mixing zone, which is induced by the impulsive acceleration of the interface between two gases of different densities. The turbulent phase of the evolution of this instability is of interest here. The thickness of the turbulent mixing zone is inferred from two different diagnostic techniques: measurements of infrared emission of CO2and black‐and‐white or color schlieren photographs. Following an assessment of the diagnostic techniques, discussions of the main experimental difficulties as the presence of membrane fragments and the disturbances induced by the wall boundary layers, are given. Comparisons of the thickness and the thickness growth rate of the turbulent mixing zones obtained in the present experiments, with both experimental and theoretical results, are made. A tentative picture of the evolution in time of the turbulent mixing zone thickness has been developed. Results fall between the predictions of the linear and thet2/3power law theories, with a tendency toward the latter one. ©1996 American Institute of Physics.