Background: Advanced age is a significant risk factor for aggressive Endometrial Cancer (EC). Myometrial invasion must be precisely diagnosed and evaluated preoperatively to make plan of the surgical procedure and optimize the prognosis. Histopathology is the confirmatory investigation to assess depth of myometrial invasion and tumour grade. Aim: The objective was to determine how age affects tumour grade and myometrial invasion in endometrial cancer, as well as to evaluate MRI accuracy in detecting preoperative myometrial invasion. Materials and Methods: This was a part of a large cross-sectional analytical study was conducted from January 2022 to December 2022. Purposive sampling was used to include 50 referred patients with biopsy-confirmed endometrial cancer in the Department of Gynaecological Oncology of BSMMU and NICRH. All patients provided written informed consent for the collection and processing of their data for scientific purposes and the patients were informed about the goal of the study. MRI was used to assess myometrial invasion preoperatively. Results: A total of 52% participants were in 51-60 years age group. The association between age with grade of tumour and deep myometrial invasion were (in MRI and histopatholgy) significantly associated (p<0.05 in patients aged 51-60 years old). MRI findings confirmed 23 (46%) and 27 (54.0%) patients had superficial and deep invasion respectively. The sensitivity, specificity, accuracy, PPV and NPV of MRI to detect myometrial invasion were 91.3%, 77.8%, 84.0%, 77.8%, and 91.3% respectively. Conclusion: The influence of age on tumour grade and deep myometrial invasion were found significant in patients aged 51 to 60 years, as observed in both MRI and histopathology. Evaluating myometrial invasion is crucial for preoperative staging of EC.