AIM: To explore the correlation between the expression levels of microRNA-377-3p(miR-377-3p)and microRNA-365-3p(miR-365-3p)in serum and aqueous humor and the degree of diabetes macular edema(DME).METHODS: A total of 60 DME patients(60 eyes)admitted to 363 Hospital from February 2021 to February 2022 were selected in this prospective study(the severe eye was selected if both eyes had DME, while the right eye was selected if the same degree of DME), including 24 mild eyes, 21 moderate eyes and 15 severe eyes. In addition, another 60 patients(60 eyes)with type 2 diabetes(without fundus disease)admitted to our hospital during the same period were selected as the control group. The basic clinical data of all subjects were collected, including body mass index(BMI), smoking history, drinking history, hypertension, hyperlipidemia, the course of diabetes, glycated hemoglobin levels, fasting blood glucose and homocysteine(Hcy); the expression levels of miR-377-3p and miR-365-3p were detected by real-time fluorescent quantitative PCR(qRT-PCR).RESULTS: The course of diabetes, glycosylated hemoglobin, fasting blood glucose and Hcy in DME group were obviously higher than those in control group(all P<0.05); the expression levels of miR-377-3p and miR-365-3p in serum of patients in DME group were lower than those in control group(all P<0.05); the expression levels of miR-377-3p and miR-365-3p in serum and aqueous humor in severe group were obviously lower than those in moderate group and mild group, and those in moderate group were obviously lower than those in mild group(all P<0.05); the expression levels of miR-377-3p and miR-365-3p in serum were negatively correlated with central macular thickness(CMT; r=-0.342, -0.374, all P<0.05), the expression levels of miR-377-3p and miR-365-3p in aqueous humor were negatively correlated with CMT(r=-0.425, -0.503, all P<0.05); the multivariate Logistic regression analysis showed that the course of diabetes, increased fasting blood glucose and Hcy were risk factors for DME in type 2 diabetes patients, and serum miR-377-3p and miR-365-3p were protective factors for DME in type 2 diabetes patients(P<0.05).CONCLUSION: The expression of miR-377-3p and miR-365-3p in serum and aqueous humor of patients with DME is low, which is negatively related to the severity of DME patients.