Continuous Subcutaneous Insulin Infusion (CSII) is considered an effective therapeutic approach to the treatment of patients with Type 1 Diabetes Mellitus (T1DM). Literature offers limited information regarding the quality of life (QoL) in patients using CSII. The aim of the study was to investigate the impact of diabetes related factors on the QoL of patients with T1DM on CSII treatment, in a Greek urban population. A cross-sectional study was conducted on 80 patients with T1DM using CSII. [(Mean±SD) age: 35.9±11.4 years, duration of diabetes: 24.2±10.3 years, BMI: 24.6±3.5kg/m2, duration of Insulin pump use: 7.1±3.9 years, HbA1c: 7.7±1.1%, gender: 37 males-43 females)]. QoL was assessed using the patient self-administered EuroQol EQ 5D validated in Greek. Correlation and regression analyses were performed to examine the relationship between EQ index - EQ VAS scores and diabetes related factors. Hypoglycemia Awareness was measured using Clarke and Gold Score questionnaires, Hypoglycemic Episodes were expressed as number of episodes per week and the Fear of Hypoglycemia was measured using the worry subscale of the Hypoglycemia Fear Survey (HFS-W). Results were as follows: Gold score: 2.8±1.5, Clarke score: 2.8±2.1, Hypoglycemia Fear Score: 20.6±11.2, Number of hypoglycemic Episodes per week: 4.3±2.9, VAS score: 68.7±18.1, EQ index: 0.79±0.24. In univariate analyses QoL was negatively correlated with Hypoglycemic episodes, HbA1c, Hypoglycemia Fear Score and Hypoglycemia Awareness status. After regression analysis, only HbA1c and the number of hypoglycemic episodes per week remained independently related to QoL scores. Prevention of hypoglycemia and glycemic control should be emphasized in order to improve QoL in patients with T1DM with CSII.