Glow discharge optical spectroscopy (GDOS) has been applied to the measurement of impurity profiles in boron‐diffused and ion‐implanted Si samples. The GDOS technique provides a convenient and sensitive probe of boron impurity profiles; results are presented for concentrations below 5×1017cm−3. For a Si sample which has been subjected to a 1‐h constant source boron diffusion at 1100°C, the measured profile exhibited enhanced diffusion effects typical of previously reported results measured by other techniques. Similarly, a sample implanted with 120‐keV B+ions to a fluence of 1014cm−2exhibited a typical boron distribution. The position of the measured peak concentration corresponded well with that predicted by theory, and the implanted distribution exhibited a prominent tail as reported from other measurements.