Continuous technological progress has occurred in improving the operational lifetime, decreasing the size, increasing the output power and improving the reliability of low- to medium-power CO2 lasers. A summary of the progress which has led to the present state-of-the-art, along with a projection of future technological trends in low- to medium-power CO2 lasers, is presented. The summary includes a discussion of RF excitation technology, folded waveguide lasers and waveguide array technology.