The impact of blood glucose-lowering medications on weight has always been a topic of interest in the treatment of diabetic patients. This study investigates the effect of empagliflozin on weight in patients with prediabetes and type 2 diabetes. This quasi-experimental study was performed on patients with prediabetes or type 2 diabetes with an HbA1c level up to 1% higher than the treatment target, and not using other blood glucose-lowering medications. Patients received 10 milligrams of Empagliflozin once daily for three months, and weight, BMI, waist circumference, and blood pressure were evaluated monthly. Forty-three patients (21 women and 22 men) enrolled. The average weight of patients decreased by 2.96 ± 1.96 kg (3.8%) (P < 0.001). BMI decreased by -1.10 ± 0.71 Kg/m (3.72%) (P < 0.001). The waist circumference of patients decreased by -3.23 ± 3.69 centimeters (P < 0.001). FPG decreased from 114.86 to 109.48 mg/dL (P < 0.001), and HbA1c decreased from 6.52% to 6.38% (P < 0.001). The weight change was more significant in men than women (-3.59 ± 1.74 vs. -2.30. ± 1.99), (P = 0.029). Weight reduction was greater in patients with GFR higher than 90 compared to GFR lower than 90 (-3.34. ± 2.00 vs. -2.16 ± 1.67) (P = 0.063). Also, no significant difference was observed in the weight, BMI, and waist circumference changes between different BMI groups (less than 25, 25 to 30, 30 to 35, and higher than 35). The trend of weight and BMI changes during the three-month empagliflozin treatment period was significant (P < 0.001) and didn't reach a plateau level after three months. The change in waist circumference was also significant, reaching a plateau level after one month (P < 0.001). There was no significant change in blood pressure. In conclusion the weight, BMI, and waist circumference of patients decreased following the administration of empagliflozin. Weight reduction was more pronounced in males than females and in patients with a GFR above 90 than those with a GFR below 90. Trial registration: This study was approved by the Research Deputy of Kerman University of Medical Sciences with tracking number 401,000,516, IRCT code: IRCT20090317001774N10, and ethical code: IR.KMU.AH.REC.1402.065 was approved by Research Ethics Committee of Afzalipour Hospital- Kerman University of Medical Sciences.