An R0 margin width of 1 cm has traditionally been considered a prerequisite to minimize local recurrence and optimize survival following hepatic resection for metastatic colorectal cancer. However, recent data have called into question the prognostic importance of the ‘1-cm rule’. Specifically, several studies have noted that, although an R0 resection is important, the actual margin width may not be as critical. We provide a brief overview of the impact of an R1 vs. an R0 resection on local recurrence and overall survival. In addition, we specifically review the impact of margin width in patients who have undergone an R0 resection. Finally, we highlight those factors most associated with an increased likelihood of an R1 resection and provide recommendations for avoiding and dealing with microscopic carcinoma discovered intraoperatively at the cut parenchymal transection margin.