Neuregulin‐1 (NRG‐1)/erythroblastic leukaemia viral oncogene homologues (ErbB) pathway activation plays a crucial role in regulating the adaptation of the adult heart to physiological and pathological stress. In the present study, we investigate the effect of recombined human NRG‐1 (rhNRG‐1) on mitochondrial biogenesis, mitochondrial function, and cell survival in neonatal rat cardiac myocytes (NRCMs) exposed to hypoxia/reoxygenation (H/R). The results of this study showed that, in the H/R‐exposed NRCMs, mitochondrial biogenesis was impaired, as manifested by the decrease of the expression of peroxisome proliferator‐activated receptor gamma coactivator‐1 alpha (PGC‐1α) and mitochondrial membrane proteins, the inner membrane (Tim23), mitofusin 1 (Mfn1), and mitofusin 2 (Mfn2). RhNRG‐1 pretreatment effectively restored the expression of PGC‐1α and these membrane proteins, upregulated the expression of the anti‐apoptosis proteins Bcl‐2 and Bcl‐xL, preserved the mitochondrial membrane potential, and attenuated H/R‐induced cell apoptosis. Blocking PGC‐1 expression with siRNA abolished the beneficial role of rhNRG‐1 on mitochondrial function and cell survival. The results of the present study strongly suggest that NRG‐1/ErbB activation enhances the adaption of cardiomyocytes to H/R injury via promoted mitochondrial biogenesis and improved mitochondrial homeostasis.Significance of the StudyThe results of this research revealed for the first time the relationship between neuregulin‐1 (NRG‐1)/erythroblastic leukaemia viral oncogene homologues (ErbB) activation and mitochondrial biogenesis in neonatal cardiomyocytes and verified the significance of this promoted mitochondrial biogenesis in attenuating hypoxia/reoxygenation injury. This finding may open a new field to further understand the biological role of NRG‐1/ErbB signalling pathway in cardiomyocyte.