OBJECTIVE To characterize glucose levels during daily living using continuous glucose monitors (CGMs) in nondiabetic individuals. RESEARCH DESIGN AND METHODS Seventy-four healthy children, adolescents, and adults aged 9–65 years with normal glucose tolerance used a blinded CGM device for 3 to 7 days. RESULTS Sensor glucose concentrations were 71–120 mg/dl for 91% of the day. Sensor values were ≤60 or >140 mg/dl for only 0.2% and 0.4% of the day, respectively. Sensor glucose concentrations were slightly higher in children than adults (P = 0.009) and were slightly lower during the night than day (95 vs. 99 mg/dl, P < 0.001). CONCLUSIONS Glucose values ≤60 and >140 mg/dl, measured with CGM, are uncommon in healthy, nondiabetic individuals. CGM may be useful to evaluate glucose tolerance in nondiabetic individuals over time. Furthermore, these data provide a basis for comparison for studies that use CGM to assess glucose control in subjects with diabetes.