Lymph node status has great clinical importance in the management of patients with colorectal cancer. Several pathologic factors may affect the accuracy of nodal status assessment in this tumor type. The aim of the present study was to evaluate, in a series of 166 stage II and stage III colorectal adenocarcinomas, the following pathologic parameters: number of lymph nodes recovered and examined, number of lymph nodes with metastases, and number of tumor nodules (TNs) in the perirectal or pericolic adipose tissue greater or smaller than 3 mm in diameter (TNs > 3 mm and TNs < 3 mm, respectively). The prognostic significance of these parameters, as well as of other histopathologic variables, was determined using univariate and multivariate survival analyses. Our results indicate that the examination of a small number of regional lymph nodes may result in understaging of tumors classified as pN0 (stage II). In addition, our data suggest that TNs > 3 mm and TNs < 3 mm represent distinct pathologic entities. TNs > 3 mm should be considered the prognostic equivalent of lymph node metastases as recommended by the 1997 TNM classification. In contrast, TNs < 3 mm probably originate by intravascular or perivascular tumor extension. Their presence is associated with adverse clinical outcome in stage III patients, regardless of the number of lymph node metastases.