Background: Larger dishware sizes have been shown to increase food portion sizes served and consumed by adults and children. Less is known about whether dishware size and design influences the amount of food caregivers serve to children. Whether smaller portion design plates can be used to help parents serve age-appropriate portion sizes to their children is unknown. This research is the first to examine the effects of dishware size and design on portion sizes served by caregivers. Methods: A within-subjects quasi-experimental design was used to determine the effects of dishware size and design on the portion sizes served by low-income caregivers to their preschool aged children during a buffet style meal. Three plate conditions were compared: a portion design plate, a plain child size plate, and an adult size plate. We hypothesized that when using the portion design plate, caregivers would serve the smallest amount of food compared to when using either the plain child size plate or the adult size plate. The amount of food served by caregivers to children was assessed using weighted methods. Results: The total amount of food (g) and energy (kcal) served did not differ across dishware conditions. Conclusions: Dishware size and design did not influence portion sizes served by caregivers. Additional factors may affect caregiver serving behaviors. / Epidemiology