Background <p>The EQ-5D-Y-3L is a generic, preference-accompanied health measure intended for pediatric populations. EQ-5D-Y-3L health states are valued using the perspective of a hypothetical 10-year-old child (‘child perspective’) rather than adults valuing for themselves (‘adult perspective’). The perspective used has been shown to influence valuation outcomes, affecting comparability of health utilities. This study explored within-respondent differences in values between adult and child perspectives using data from Hungary.</p> Methods <p>A secondary analysis was conducted using composite time trade-off (cTTO) data from the Hungarian EQ-5D-Y-3L valuation study. Two hundred adults valued 10 health states from the child perspective and four from the adult perspective. The cTTO values for the matched health states (valued from both perspectives) were compared, with differences analyzed using t-tests and random-intercept regression. Associations with respondent characteristics were also explored.</p> Results <p>Differences in cTTO values were observed between perspectives, particularly for more severe health states. Compared to the adult perspective, the child perspective yielded significantly lower values for worse-than-dead observations, but higher values for better-than-dead observations. After adjusting for within-subject variation and respondent characteristics, perspective was not a significant predictor of cTTO values. Instead, differences were partly explained by education, region of residence, parental status, and the view that a child’s life is more valuable than an adult’s.</p> Conclusions <p>This is the first study to explore perspective differences in EQ-5D-Y-3L health state valuation within respondents using nationally representative data from outside Western Europe. The findings highlight the importance of considering individual-level attributes in pediatric health valuation.</p>