The objective of the current study was to assess the factor structure of the Illness Behavior Encouragement Scale (IBES) by Walker and Zeman (1992) among children with functional gastrointestinal disorders (FGIDs). Two hundred seventy nine children (63 % female), and 135 primary caregivers (90.8 % mothers), recruited from a large Midwestern children's hospital completed the IBES, a 12-item measure of parental behavior in response to abdominal pain episodes. Findings suggested the IBES possesses two conceptually distinct scales that are invariant across parent self- and child-report, and are consistent with previous factor analysis in a Dutch sample of children with headaches. Different types of parental behaviors exist that naturally cluster and diverge in reliable ways. Future research is warranted to determine if these different types of parental behavior may differentially influence illness outcomes among children with FGIDs.