OBJECTIVE: This multicenter, parallel-group, randomized trial examined the effects of an animal-assisted intervention on the stress, anxiety, and health-related quality of life for children diagnosed with cancer and their parents. METHOD: Newly diagnosed patients, aged 3 to 17 years (n = 106), were randomized to receive either standard care plus regular visits from a therapy dog (intervention group), or standard care only (control group). Data were collected at set points over 4 months of the child’s treatment. Measures included the State-Trait Anxiety Inventory, Pediatric Quality of Life Inventory, Pediatric Inventory for Parents, and child blood pressure and heart rate. All instruments were completed by the child and/or his/her parent(s). RESULTS: Children in both groups experienced a significant reduction in state anxiety ( P < .001). Parents in the intervention group showed significantly decreased parenting stress ( P = .008), with no changes in stress among parents in the control group. However, no significant differences between groups over time on any measures were observed. CONCLUSIONS: Animal-assisted interventions may provide certain benefits for parents and families during the initial stages of pediatric cancer treatment.