The recent discovery of several new endogenous opioid peptides has generated excitement over their potential physiological roles. For example, endomorphins are likely to have well defined functions due to their affinity and selectivity for a class of extensively studied opioid receptors (1). However, nociceptin/orphanin FQ is an endogenous opioid-like peptide with less well defined effects on animal physiology and behavior (47). A study published in this issue by Jenck et al. (2) proposes a novel function for this peptide, a potential role in modulating anxiety and/or behavioral responses to stressors. These new findings may change the direction of nociceptin/orphanin FQ research as well as add another candidate for novel anxiety therapies.