To assess the agreement between preoperative endometrial sampling and final diagnosis for tumor grade and subtype in patients with endometrial carcinoma. MEDLINE, EMBASE, ClinicalTrials.gov, and the Cochrane library were searched from inception to January 1, 2017, for studies that compared tumor grade and histologic subtype in preoperative endometrial samples and hysterectomy specimens. In eligible studies, the index test included office endometrial biopsy, hysteroscopic biopsy, or dilatation and curettage; the reference standard was hysterectomy. Outcome measures included tumor grade, histologic subtype, or both. Two independent reviewers assessed the eligibility of the studies. Risk of bias was assessed (Quality Assessment of Diagnostic Accuracy Studies). A total of 45 studies (12,459 patients) met the inclusion criteria. The pooled agreement rate on tumor grade was 0.67 (95% CI 0.60-0.75) and Cohen's κ was 0.45 (95% CI 0.34-0.55). Agreement between hysteroscopic biopsy and final diagnosis was higher (0.89, 95% CI 0.80-0.98) than for dilatation and curettage (0.70, 95% CI 0.60-0.79; P=.02); however, it was not significantly higher than for office endometrial biopsy (0.73, 95% CI 0.60-0.86; P=.08). The lowest agreement rate was found for grade 2 carcinomas (0.61, 95% CI 0.53-0.69). Downgrading was found in 25% and upgrading was found in 21% of the endometrial samples. Agreement on histologic subtypes was 0.95 (95% CI 0.94-0.97) and 0.81 (95% CI 0.69-0.92) for preoperative endometrioid and nonendometrioid carcinomas, respectively. Overall there is only moderate agreement on tumor grade between preoperative endometrial sampling and final diagnosis with the lowest agreement for grade 2 carcinomas.