There is uncertainty on the best approach to histological examination of macroscopically negative lymph nodes obtained from resections for colorectal carcinomas. In this study we reviewed the lymph nodes from all 54 colorectal resections for colorectal carcinoma with positive lymph nodes obtained in 1 year. Macroscopically negative nodes had been sliced and all the tissue embedded. There were 20 lymph nodes that had a metastasis seen in only one section of the sliced node, from 13 resections; 6 patients could have had their staging changed if the nodes had been sampled rather than all embedded and examined. The median size of the smallest metastasis for each patient was 2 mm. We suggest that all tissue from macroscopically negative lymph nodes should be examined.