Background: Evidence on the incidence and risk factors for lower limb lymphedema (LLL) associated with endometrial cancer is limited. Our objective was to use data from a prospective, longitudinal gynecological cancer cohort study to determine LLL incidence up to 24 months post-diagnosis of endometrial cancer and to explore the relationship between personal and treatment-related factors and risk of developing LLL. Methods: Women recently diagnosed with endometrial cancer (n = 235) were evaluated at regular intervals post-diagnosis (up to 3-monthly) using bioimpedance spectroscopy (BIS) and self-reported leg swelling (SRLS). Results: Incidence of LLL at 24 months post-diagnosis was 33% and 45% according to BIS and SRLS, respectively. When analyses were restricted to obese women, incidence at 24 months post-diagnosis increased to 67% (BIS) and 54% (SRLS). Following adjusted analyses, higher body mass index was associated with higher odds of baseline lymphedema (BIS: OR 1.91, 95% CI 1.47-2.49, p < .01; SRLS: OR 1.06, 95% CI 1.00-1.12, p < .01) and LLL incidence by 24 months post-diagnosis (BIS: OR 1.29, 95% CI: 0.99-1.68, p = .055; SRLS: OR 1.06, 95% CI 1.02-1.11, p = .008). According to SRLS, presence of comorbidities was also associated with baseline lymphedema (OR: 1.43, 95% CI: 1.15-1.78, p = .001), and more extensive lymph node dissection (OR 1.06, 95% CI: 1.01-1.12, p = .026) and receipt of chemotherapy (OR: 2.65, 95% CI: 1.12-6.29, p = .027) were identified as risk factors for lymphedema incidence. Conclusions: These findings suggest that LLL following endometrial cancer is common, particularly in women with high body mass index, or comorbidities, and those requiring more extensive lymph node dissection or chemotherapy. Future studies should examine the potential of weight loss intervention as a strategy to reduce LLL incidence.