Multigenerational studies became of great interest in ecotoxicology since the consequence of parental exposure on offspring generations has been established in situ or in laboratory conditions. This study mainly examined chronic effects of external Cs-137 gamma irradiation exposure at 4 dose rates (control, 0.5, 5 and 50 mGy h-1) on adult zebrafish (F0) exposed for 10 days and its progeny (F1) exposed for 4 days. The main investigated endpoints included parental reproductive performance, embryo-larval survival, DNA alterations and ROS production in F0 and F1. No effects on reproductive success, fecundity or egg fertilization rate were observed. However, drastic effects were observed on F1 at the highest dose rate, resulting in a mortality of 100%. The drastic effects were also observed when the progeny was not irradiated. We demonstrate that the sensitivity of the embryos was mainly due to parental irradiation. Moreover, these drastic effects induced by adult irradiation disappeared over time when 10 d- irradiated adults were placed in a non-irradiated condition. DNA alterations in larvae were observed for the three dose rates, with an increase of ROS production was also shown for the two lowest dose rates. This study improves our understanding of the consequences of multigenerational exposure conditions. Furthermore, it incentivizes us to take into account transmitted generational effects in ecological risk assessments.Read less <