Hematopoietic stem and progenitor cells (HSPCs) have the capacity to self-renew and differentiate into all blood cell lineages, and thus sustain life-long homeostasis of hematopoietic system.Although intensive studies have focused on the orchestrated genetic network of HSPC specification and expansion, relatively little is known on the regulation of HSPC survival during embryogenesis.Here, we generated two types of miR-142a-3p genetic mutants in zebrafish, and showed that the loss-of-function mutants displayed severe reduction of HSPCs.Further analysis showed that the diminished proliferation and excessive apoptosis in miR-142a-3p mutants were attributed to the increased p53 signaling.Mechanistically, we demonstrated that miR-142a-3p directly targets p53 during HSPC development and the HSPC survival defect in miR-142a-3p mutants could be rescued by loss of p53.Therefore, our work reveals the significance of miR-142a-3p-p53 pathway in controlling HSPC survival and thus advances our understanding of the role of p53 in vertebrate hematopoiesis.