The increasing incidence of colorectal cancer in Morocco has generated a need for a disease-specific quality-of-life measuring instrument. The present study aims to translate and evaluate the reliability and validity of the Moroccan Arabic version of the EORTC QLQ-C29 measure in Moroccan subjects with colorectal cancer (CRC). Methods:Following translation to Moroccan Arabic, The QLQ-C30 and QLQ-C29 were administered to 135 patients treated for colorectal cancer (CRC) at the national oncology institute of Rabat, in the period from February 2016 to June 2018. Statistical analysis included reliability, convergent, and discriminant validity as well as known-groups comparisons. Results:(89 %) patients completed the questionnaires of the EORTC QLQ C-29 and EORTC QLQ C-30. The test –retest, administered to 25 patients and the ICCs for each item ranged from 0.61 to 0.93 indicating good to excellent reproducibility. The internal consistency coefficients for body image, urinary frequency, stool frequency scales were acceptable (Cronbach’s alpha ≥ 0.70), while the blood and mucus in the stool dimensions had lower reliability (0.65). Multi-trait scaling analysis showed that multi-item scales met standards of convergent and discriminate validity. All Correlations between the EORTC QLQ C-29 and EORTC QLQ C-30 scores were low (r < 40). The known- group comparisons showed differences between group of patients based on tumor location and with/ without a stoma. Conclusion:The Moroccan Arabic Dialectal version of the QLQ-C 29 is a valid and reliable measure of health related quality of life (HRQOL) in patients with colorectal cancer.