Background: Endometrial carcinoma (EC) is a common gynecologic malignancy with significant implications for women's health. Mismatch repair deficiency (MMRd) has emerged as a critical factor influencing the pathogenesis and prognosis of EC. This study aims to investigate the clinicopathologic characteristics of MMRd EC in a Bangladeshi cohort. Methods: This cross-sectional observational study was conducted at the Department of Gynecological Oncology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, from March 2022 to February 2023. A total of 49 patients with histologically confirmed EC were included. Data were collected through a semi-structured questionnaire and patient records. Results: Among the 49 patients, 67.35% (n=33) were MMR proficient, while 32.65% (n=16) were MMR deficient. The mean age was 55 years for MMR proficient and 55.6 years for MMR deficient patients. Hypertension was present in 69.70% of MMR proficient and 75% of MMR deficient patients, while diabetes mellitus affected 54.55% of MMR proficient and 62.50% of MMR deficient patients. MMRd patients showed higher rates of adnexal involvement (37.50% vs. 6.06%, p=0.010) and metastasis (37.50% vs. 9.09%, p=0.024). Multivariate logistic regression identified advanced FIGO stage (III & IV) as a significant predictor of MMR deficiency (adjusted OR 4.274, 95% CI: 1.691-15.515, p=0.025). Conclusion: MMRd in endometrial carcinoma is associated with more aggressive tumor features and poorer prognostic indicators. Routine evaluation of MMR status is crucial for effective prognosis and treatment planning. Addressing socioeconomic disparities and integrating targeted therapeutic strategies can improve management and outcomes for patients with MMRd endometrial carcinoma in diverse populations.