Background: Colorectal carcinoma (CRC) is the third most common cancer in the world constituting about 10% of all cancers. ALDH1A1 has been used as a stem cell marker, and plays important functional roles in stem cells. Expression of ALDH1A1 by cancer stem cells (CSCs) has been demonstrated in multiple types of cancers. Aim: This work aimed to evaluate ALDH1A1 expression in colorectal adenocarcinoma and determine the relation between ALDH1A1 expression and different clinico-pathological variables. Material and method: This is a selected retrospective study included 50 different cases of colorectal adenocarcinoma. ALDH1A1 immunostaining was performed for all cases. Results: There was a highly significant statistical difference between ALDH1A1 expression in studied cases according to tumor site, lymph node metastasis and TNM stage (P value