Spectrum synthesis techniques have been used to derive quantitative carbon and nitrogen abundances for two stars with M/sub v/approx. =0.0 in the globular cluster NGC 6752. The stars CL 25 and CL 166 have similar effective temperature and gravity but different lambda3883 CN band strength. The abundance ratios derived, relative to the other elements for which (A/H)=-1.5, are ((C/A),(N/A))+0.1, -0.2for CL 25 and (-0.2, +0.6) for CL 166. The abundance ratios for CL 166, and presumably those of the other CN-strong stars in this cluster, can be explained by the mixing of processed material into the atmosphere of the star.