The DNA repair complexes provided herein are, inter alia, useful for editing genome sequences by introducing precise changes in a target site in the presence of a donor sequence. The RNA-guided DNA endonuclease provided herein including embodiments thereof (e.g., Cas9 nuclease or Cas9 nickase) is capable of introducing a strand break (double- or single-strand break) at a target site in the genome of a cell (e.g., gene or transcriptional regulatory sequence) and the break is then predominantly repaired through the mechanism of HDR. By increasing the HDR efficiency significantly and in certain instances decreasing NHEJ at a target site, the compositions and methods provided herein meet the long-felt need of site directed, highly accurate genome editing.