Low-noise, high-resolution Reticon spectra are used to obtain C, N, and O abundances for chemically peculiar stars with surface temperatures between 7,000 and 15,000 K. The analysis includes C I, C II, N I, and O I lines for 13 Am and related stars, nine Hg-Mn stars, 15 magnetic Ap stars, and five standard stars. The C and O abundances show a roughly monotonic increase with surface temperature. The C and O results are in general agreement with radiative diffusion theory. The N abundances, however, show that N is slightly deficient in cool nonmagnetic stars and very deficient above 10,000 K in nonmagnetic stars. The results for N disagree with simple diffusion predictions, suggesting that a more detailed model is needed for partially ionized N near the stellar surface. 101 refs.