Rho family GTPases play a pivotal role in the regulation of numerous cellular functions associated with malignant transformation and metastasis. To evaluate the role of these GTPases in colorectal cancer, the protein expression levels and activities of these proteins in matched sets of tumor and non-tumor tissues of surgical specimens were analyzed. The relationship between the protein levels and activities in tumor tissues to the clinicopathological features was also assessed. The expression levels of RhoA, active RhoA, Rac1, and active Rac1 in tumor tissues were higher than in normal tissues. The amounts of active RhoA protein in primary tumors correlated with lymph nodes metastasis. No relationship was noted between the protein expression levels and other clinicopathological findings. These findings suggest that the Rho family small GTPases are related to malignant transformation and progression of colorectal cancer and the activation of RhoA is associated with the lymph node metastasis.