The line shape and change in frequency of the line center have been accurately determined for the S0(0) and S0(1) rotational Raman lines of normal H2 at densities from 2 to 38 amagat, and for the S0(1) line for mixtures of normal H2 in helium and argon at total densities from 7 to 85 amagat. For pure H2 the absolute Raman displacement extrapolated to zero gas density was also measured for both rotational lines. The accuracy obtained, ± 0.002 cm−1, results from the application of interferometric techniques to Raman spectroscopy and represents about an order of magnitude improvement over earlier measurements.