Global vaccination against the coronavirus disease 2019 (COVID-19) is thought to be the most effective way to end or at least contain the COVID-19 pandemic. However, despite the good safety profiles and effectiveness of the available COVID-19 vaccines, rare but serious hematological complications have emerged, including thromboembolic outcomes with thrombocytopenia following the ChAdOx1 nCoV-19 (Oxford-AstraZeneca) and Ad26.COV.2.S (Johnson & Johnson/Janssen) vaccines. Moreover, COVID-19 vaccination may be linked to the development of aplastic anemia (AA). We discuss four cases of AA that arose after COVID-19 vaccination in our hospital and two other such cases identified in our literature review.