BACKGROUND: The most appropriate preference-based health-related quality of life (HRQoL) instruments for trials or research studies that ascertain the consequences of individuals born very preterm and/or low birthweight (VP/VLBW) are not known. Agreement between the HUI3 and SF-6D multi-attribute utility measures have not been previously investigated for VP/VLBW and normal birthweight or term-born controls. This study examined the agreement between the outputs of the HUI3 and SF-6D measures among adults born VP/VLBW and normal birthweight or term born controls. METHODS: We used two prospective cohorts of individuals born VP/VLBW and controls contributing to the 'Research on European Children and Adults Born Preterm' (RECAP) consortium which assessed HRQoL using two preference-based measures. The combined dataset of individual participant data (IPD) included 407 adult VP/VLBW survivors and 367 controls, ranging in age from 18 to 26 years. Bland-Altman plots, intra-class correlation coefficients, and generalized linear mixed models in a one-step approach were used to examine agreement between the measures. RESULTS: There was significant discordance between the HUI3 and SF-6D multi-attribute utility measures in the VP/VLBW sample, controls, and in the combined samples. Agreement between the HUI3 and SF-6D multi-attribute utility measures was weaker in controls compared with VP/VLBW individuals. CONCLUSIONS AND RELEVANCE: The HUI3 and SF-6D each provide unique information on different aspects of health status across the groups. The HUI3 better captures preterm-related changes to HRQoL in adulthood compared to SF-6D. Studies focused on measuring physical or cognitive aspects of health will likely benefit from using the HUI3 instead of the SF-6D, regardless of gestational age at birth and birthweight status.