Abstract : Human cytomegalovirus infection has been implicated to be associated with colorectal cancer (CRC) progression and possibly in tumorigenesis. The up-regulation of Interleukin-1 IL-1 agonists (IL-1α and IL-1β) has been associated and / or implicated in recent years in promotion of tumor progression, invasiveness and metastasis of many tumors. The present study aimed to evaluate the co-expression of IL-1 beta along with HCMV infection in a group of colorectal carcinoma tissues. Eighty-one formalin-fixed, paraffin- embedded colorectal biopsies were enrolled in this study; 42 from colorectal cancers, 22 from benign tumors and 17 colorectal tissues with unremarkable pathological changes (healthy control group). Chromogenic in Situ Hybridization (CISH) was done for detecting HCMV- DNA whereas immunohistochemistry (IHC) was used to assess the expressional protein of IL-1 beta gene. The CISH reactions of HCMV-DNA were detected in 57.1 % (24 out of 42) of colorectal cancer biopsies and in 31.8 % (7 out of 22) of benign colorectal tumors biopsies. 11.7%(2\11cases) positive– CISH reactions were detected in the control tissues. The positive IL-1 beta -IHC reactions were detected in 52.4% (18 out of 42) of CRC and in 45% (13 out of 22) of benign colorectal tumors biopsies. 5.8% (1\17cases) positive IHC- signals were reported in the colorectal control tissues. Statistically, highly significant differences were present between each colorectal tumors groups and the control group for HCMV & IL-1 beta. Detection of co-expression of IL-1 beta with HCMV in colorectal carcinoma could point both for their possible roles in either colorectal pathogenesis or carcinogenesis