This study examines individual and situational influences on declining hunter effort in Illinois. Data were obtained from a self-administered mail survey of 2,872 (response rate = 67%) resident hunters in Illinois. A series of four separate logistic regressions were constructed to model demographics, past experience, and perceived personal and situational constraints related to declining hunter effort. A final model included variables from each of the separate regressions. Nine variables were significant predictors of hunter effort in the final model: four perceived personal constraints (lack of time, interest, finances, and poor health), three situational constraints (not enough game, no land available for hunting, and too many regulations), and two past experience variables (years of hunting experience and days afield during prior season). None of the demographic variables had a significant influence on hunter effort after controlling for the other predictors in the model. The final model that included past experience and the two sets of perceived constraint measures (personal and situational) explained 91% of the variance and correctly classified 97% of hunters in both the "decreased" and "did not decrease" categories. Discussion focuses on the need for understanding perceived constraints to hunting participation that are within the control of management agencies.