Fluorescence in situ hybridization (FISH) is an easy and efficient means of measuring numerical chromosome aberrations in the interphase nuclei of solid tumors; however, the correlation between numerical chromosome aberrations and the clinical stage of solid tumors remains unknown. Thus, in the present study, we investigated the relationship between numerical chromosome aberrations and clinicopathologic features in colorectal adenocarcinomas. FISH was applied to surgically resected colorectal cancer samples from 45 patients to evaluate the numerical aberrations of chromosomes 11 and 17. The mean age of the patients was 65.1 years, and they comprised 13 women and 32 men. According to Dukes' classification, 5 patients were categorized as stage A, 21 as stage B, 10 as stage C, and 9 as stage D. Histologically, 18 of the samples were lymph node metastasis-positive. FISH revealed numerical aberrations of chromosome 11 in 27 out of the 45 patients (60%), and those with a lower chromosome 11 number had a significantly lower incidence of lymph node metastasis (P < 0.05). Chromosome 17 proved to have numerical abnormalities in 33 of the 45 patients (73%), and those with a higher chromosome 17 number had more DNA aneuploidy (P < 0.005). This is the first report to reveal the relationship between monosomy 11 and lymph node metastasis in colorectal adenocarcinomas.