Measurements of the interactions of CO2laser radiation with a theta pinch plasma have been made using laser scattering as a diagnostic technique. The plasma was heated axially with a TEA CO2pin laser. The scattering measurements have shown the time evolution of the laser−heated plasma during and after heating by the ’’spike’’ of the CO2laser. The energies involved in the change of plasma conditions agree well with the theoretical absorption associated with the inverse bremsstrahlung mechanism.