Background/Aims: The relationship between fasting blood glucose (FBG) variability and colorectal cancer (CRC) remains ill-defined. This study aimed to evaluate the association of FBG variability with CRC risk in the healthy population without overt diabetes. Methods: In the data from the Korean National Health Insurance Service-Health Screening Cohort, we included individuals examined by FBG testing at least 3 times between 2002 and 2007. FBG variability was calculated using standard deviation (SD) and coefficient of variation (CV). Results: Regarding FBG variability, an increase in the quintile of SD or CV was independently associated with CRC risk (all p for trend <0.01). When the change in FBG was classified into six trajectory patterns, unfavorable trajectory patterns (high stable and upward) were significantly associated with increased CRC risk (hazard ratio [HR] 2.30, p=0.003; HR 1.19, p=0.007, respectively). In subgroup analyses according to the sex, a significant association between FBG variability (SD or CV) and CRC risk was observed in men but not in women. The high stable and upward pattern were also associated with CRC risk in men (HR 2.47, p=0.002; HR 1.21, p=0.012) but not in women. Conclusions This study identified that FBG variability and unfavorable trajectory patterns were significantly associated with increased CRC risk in the healthy population without overt diabetes. Our findings suggest that FBG variability as well as FBG itself may be a predictive factor for the development of CRC.