Are there differences in terms of under-5 mortality (U5M) depending on whether one is born to an immigrant or a native parent? This is the question that this paper addresses using the permanent demographic sample, the largest French sociodemographic panel with a sample of 657,548 births from 1990 to 2019. Parental origin is measured by the mother’s country of birth grouped into 5 regions: Sub-Saharan Africa, North Africa, Asia, Europe, America-Oceania & Other compared to the french natives. Two parametric longitudinal Weibull models were implemented. The first one is an unadjusted model whose results show an excess U5M among children of immigrant mothers, with the exception of those from Europe and Asia. As for the second model, it was implemented by considering the weighting by the inverse of the probability of treatment. Indeed, the differences in terms of socioeconomic characteristics between immigrants and natives (in favor of the latter) make them incomparable. We therefore proceeded to rebalance them on the basis of covariates relating to standard of living, socio-professional category and level of education, which have been proven to be favorable to the natives. These covariates were used to construct the propensity score, which was then used to assign a weight to each individual according to the inverse probability of treatment method. At the end of this process, the results not only confirm an excess U5M of immigrants (except for the case of Europe), including those of mothers born in Asia, but a higher excess mortality for most children of immigrants. To ensure our findings were robust to different methods based on propensity score, we conducted sensitivity analysis by re-fitting the propensity score method using matching method based on the same propensity score and compared it to Inverse Probability of Treatment Weighting (IPTW) method. The findings from this sensitivity analysis confirmed the main result even though it slightly overestimates the effect of the category "America-Oceania & other”. In short, we can conclude that Mother origin plays an essential role in the construction of inequalities especially in terms of under-5 mortality. These inequalities remain and are reinforced after adjusting for socioeconomic characteristics; which can be indicative of discrimination.