The use of spontaneous rotational and vibrational Raman scattering for nonperturbing measurements of temperature and gas phase concentrations in combustion and in materials processing is reviewed. Theory of Raman intensities is briefly discussed and examples of Raman scattering from metal halide vapors in high temperature furnaces, laminar flames, and turbulent flames are given to demonstrate its capabilities and limitations. At present spontaneous Raman scattering is the only method which can provide simultaneous nonperturbing measurements of temperature and many species concentrations with high spatial (≤ 0.1 mm3) and temporal (≤ 1μs) resolution. Rotational Raman scattering is generally preferred for low temperature measurements (≤ 1200 K), and vibrational Raman scattering is better for measurements of higher temperatures and of multiple-species concentrations. The disadvantages of Raman scattering stem for the weakness of the nonresonant Raman interaction which limits its sensitivity to major species concentrations, renders it vulnerable to interferences from other sources of visible radiation, and requires high powered lasers and sensitive detectors. Data from Raman scattering measurements, particularly when coupled with data from other laser diagnostic techniques and when compared to computer model calculations, have led to a better understanding of the complex interactions between fluid mechanics and chemical reactions which can govern the operation of turbulent combustors or chemical flow reactors.