Introduction and Objective. The ability to perceive the symptoms of hypoglycemia during the early decrease in plasma glucose concentration may be critical for the safety of T1DM patients treated with intensive insulin therapy, including those treated with continuous subcutaneous insulin infusion (CSII). In the presented observational study an attempt was made to asses clinical factors that might affect subjective awareness of hypoglycemia in CSII-treated T1DM patients, with special attention to factors specific for this mode of treatment. Materials and Methods. For the purpose of the study, data of 110 CSII-treated T1DM patients were collected (78 females and 32 males). The records were analyzed from glucose meters (200-300 measurements/download, depending on meter type) and insulin pumps (total insulin dose, basal/bolus ratio, number of boluses/day, bolus calculator and dual wave/square bolus usage, continuous glucose monitoring data) from the last 3 years. Results. It was found that the level of subjective hypoglycemia perception inversely correlated with the number of hypoglycemic episodes per 100 measurements, age, duration of diabetes, time on insulin pump, and positively correlated with mean glycemia (n = 98; r = 0.22; p = 0.0286). With respect to CSII-related factors, hypoglycemia perception inversely correlated with the percentage of basal insulin (n = 106; r = -0.20; p = 0.0354). In stepwise regression analysis, independent predictors for impaired hypoglycemia perception were: age β = -0.29 (p = 0.023), duration of diabetes β = -0.24 (p = 0.029) and number of the hypoglycemia episodes for 100 measurements β = -0.33 (p = 0.0005). Conclusions. Risk factors for impaired hypoglycemia perception in CSII-treated patients include those identified previously for the general population of T1DM individuals. In addition, the presented results suggest that a higher basal/bolus ratio may lead to impairment of the ability to perceive early symptoms of hypoglycemia.