Thirty patients (ages 5 to 13) hospitalized in a pediatric oncology intensive care unit (ICU) rated the presence and severity of their pain on the Faces Pain Scale (FPS) and the Poker Chip Tool (PCT). Parents independently rated the child's pain on these scales and each patient's nurse completed the Objective Pain Scale (OPS). Patients' ratings on the FPS correlated significantly with parents' ratings on this scale (tau = .48, P = .002) but not on the PCT (tau = .23, P = .16). Nurses' ratings on the OPS were moderately correlated with patients' FPS ratings (tau = .37, P = .02) but were only weakly associated with PCT ratings (tau = .27, P = .09). The majority of patients, parents, and nurses expressed a preference for the FPS over the PCT. The FPS appears to be a clinically useful and accurate approach for measuring the pain of pediatric oncology patients in an ICU but is limited to those who can participate in a self-report measurement.