Introduction: Colorectal cancer (CRC) can induce an anti-tumoral immune response mediated by T-lymphocytes, which express CD3. Objectives: To analyze the prognostic value of tissue expression of intraepithelial CD3 (CD3I) both overall and in the early tumoral stages. Methods: We revised 251 patients with resected CRC and favorable clinical course. CD3I expression was analyzed by immunohistochemistry. Multivariate analysis was used to analyze the variables independently associated with survival. We analyzed CD3I(+) expression in relation to survival and tumoral progression, both overall and in patients with pTNM(I-II) stage tumors. The sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of CD3I expression were analyzed. Results: A total of 25.9% of patients with CRC were CD3I(+). After a mean follow-up of 74 months, CD3I(+) expression showed a favorable prognostic value for survival in the multivariate analysis (p = 0.045). Survival curves and absence of tumoral progression were more favorable in CD3I(+) cases, both overall (p = 0.009 and p = 0.004, respectively), and in stages I-II (p = 0.029 and p = 0.015). The specificity and positive predictive value of CD3I(+) were as follows: Survival: overall: specificity =0.89; positive predictive value =0.91. Stage (I-II): specificity =0.94; positive predictive value =0.98. Absence of tumoral progression: overall: specificity = 0.89; positive predictive value =0.88. Stage (I-II): specificity =0.92; positive predictive value =0.96. Conclusions: CD3I expression has an favorable independent prognostic value, with statistically significantly higher percentages of survival and absence of tumoral progression. This more favorable outcome is maintained in the less advanced stages (I-II). CD3I expression shows high specificity and positive predictive value. (C) 2012 Elsevier Espana, S.L. and AEEH y AEG. All rights reserved.