Implementation of carbon nanofibers (CNFs) in biomedical applications have successful outcomes, however, they are still considered as a potential hazard. We herein used avian embryos at 3 days and its chorioallantoic membrane (CAM) at 6 days of incubation to evaluate the impact of synthesized CNFs on the early stage of embryogenesis and angiogenesis. Our data point out that 50 μg/embryo concentration of CNFs provoke adverse effects as 75% of CNFs-exposed embryos die within 1-5 days after exposure compared with their matched controls. Furthermore, CNFs significantly inhibit angiogenesis of the CAM after 48-hours post-treatment. Additionally, RT-PCR analysis on seven key controller genes responsible for proliferation, survival, angiogenesis, and apoptosis showed that these genes are deregulated in brain, heart, and liver tissues of CNFs-exposed embryos compared to their matched control. Our investigation suggests that CNFs could have a toxic effect on the early stages of embryogenesis as well as angiogenesis. Nevertheless, further investigations are required to evaluate the effects of CNFs and elucidate their mechanism on the early stage of the normal development and human health.