AbstractMajor cell entry factors of SARS-CoV-2 are present in neurons; however, the neurotropism of SARS-CoV-2 and the phenotypes of infected neurons are still unclear. Acute neurological disorders occur in many patients, and one-third of COVID-19 survivors suffer from “brain diseases”. Here, we show that SARS-CoV-2 invades the brains of five patients with COVID-19 and Alzheimer’s, autism, frontotemporal dementia or no underlying condition by infecting neurons and other cells in the cortex. SARS-CoV-2 induces or enhances Alzheimer’s-like neuropathology with manifestations of β-amyloid aggregation and plaque formation, tauopathy, neuroinflammation and cell death. SARS-CoV-2 infects mature but not immature neurons derived from inducible pluripotent stem cells from healthy and Alzheimer’s individuals through its receptor ACE2 and facilitator neuropilin-1. SARS-CoV-2 triggers Alzheimer’s-like gene programs in healthy neurons and exacerbates Alzheimer’s neuropathology. A gene signature defined as an Alzheimer’s infectious etiology is identified through SARS-CoV-2 infection, and silencing the top three downregulated genes in human primary neurons recapitulates the neurodegenerative phenotypes of SARS-CoV-2. Thus, SARS-CoV-2 invades the brain and activates an Alzheimer’s-like program.