Abstract: Colorectal cancer is known as one of the most common types of cancer which the prevalence is increasing. According to reports, malignancies of the large intestine have highly broken out in Iran. Several studies have shown the correlation between the CD34 cell surface markers and some cancers. In the present study, the relationship between the protein expression and clinico-pathologic characteristics was evaluated. In this study, 40 paraffin blocks belonged to patients with colorectal cancer referring to Imam Khomeini Hospital in Ahvaz during 2003-2013 were studied by immunohistochemistry method. From 40 samples, 22 were males and 18 females. Their mean age was 56±17.9 years and ranging from 22-87 years. The mean tumor size was 5.1 cm ranging 11-1.5 cm. The most common site of involvement was in the right colon (45%) and the rarest site in the transverse colon (10%) and 75% was in poorly-differentiated state in terms of tumor grade. Generally, marker expression was positive in 13 cases and negative in 27 cases. The CD34 expression was significantly correlated with tumor size, tumor depth, degree of differentiation as well as lymphatic, vascular and neural invasions. A positive correlation was observed between the marker expression and pathological characteristics. Therefore, CD34 marker expression can be effective as a marker in the diagnosis of pathological characteristics of colorectal cancer. However, further studies with a large population are recommended.