Aspergillus flavus is a significant human pathogen, allergen, and producer of mycotoxins. It is the second most common cause of invasive aspergillosis and the most common cause of superficial infections. A. flavus is more prevalent in air than A. fumigatus in certain regions and is more virulent, requiring 100-fold fewer spores to cause infection in mice. It is associated with chronic granulomatous sinusitis, keratitis, cutaneous aspergillosis, wound infections, and osteomyelitis. Outbreaks are often linked to single or closely related strains, unlike those of A. fumigatus. A. flavus produces aflatoxins, highly toxic and potent hepatocarcinogens. Accurate identification of A. flavus species is challenging due to overlapping characteristics, and further taxonomic and genetic studies are needed. The A. flavus complex includes 23 species, including two sexual species, Petromyces alliaceus and P. albertensis. The genome of A. oryzae is fully sequenced, while A. flavus is in the final stages of annotation. Understanding A. flavus lags behind that of A. fumigatus, and studies on genomics, taxonomy, pathogenicity, allergenicity, and antifungal susceptibility are needed. A. flavus is widely distributed, grows well in soil, and survives harsh conditions. It is prevalent in tropical countries and is a common cause of fungal infections in homes and hospitals. A. flavus can contaminate water, leading to health risks. The A. flavus genome is 36.3 Mb, with 8 chromosomes and 13,071 predicted genes. It is genetically similar to A. oryzae but is a common environmental organism. Molecular typing methods, such as RFLP, RAPD, and microsatellite analysis, are used to differentiate A. flavus strains. A. flavus is associated with a higher genetic diversity in outbreaks compared to A. fumigatus. A. flavus is a major producer of aflatoxins and other mycotoxins, and it can cause a wide range of human diseases, including keratitis, cutaneous infections, wound infections, endocarditis, pericarditis, and central nervous system infections. It is also a common cause of allergic fungal sinusitis and sinus aspergilloma. A. flavus is more virulent and resistant to antifungal drugs than many other Aspergillus species. Recent genomic studies may help better understand its pathogenesis, toxin production, and allergens.Aspergillus flavus is a significant human pathogen, allergen, and producer of mycotoxins. It is the second most common cause of invasive aspergillosis and the most common cause of superficial infections. A. flavus is more prevalent in air than A. fumigatus in certain regions and is more virulent, requiring 100-fold fewer spores to cause infection in mice. It is associated with chronic granulomatous sinusitis, keratitis, cutaneous aspergillosis, wound infections, and osteomyelitis. Outbreaks are often linked to single or closely related strains, unlike those of A. fumigatus. A. flavus produces aflatoxins, highly toxic and potent hepatocarcinogens. Accurate identification of A. flavus species is challenging due to overlapping characteristics, and further taxonomic and genetic studies are needed. The A. flavus complex includes 23 species, including two sexual species, Petromyces alliaceus and P. albertensis. The genome of A. oryzae is fully sequenced, while A. flavus is in the final stages of annotation. Understanding A. flavus lags behind that of A. fumigatus, and studies on genomics, taxonomy, pathogenicity, allergenicity, and antifungal susceptibility are needed. A. flavus is widely distributed, grows well in soil, and survives harsh conditions. It is prevalent in tropical countries and is a common cause of fungal infections in homes and hospitals. A. flavus can contaminate water, leading to health risks. The A. flavus genome is 36.3 Mb, with 8 chromosomes and 13,071 predicted genes. It is genetically similar to A. oryzae but is a common environmental organism. Molecular typing methods, such as RFLP, RAPD, and microsatellite analysis, are used to differentiate A. flavus strains. A. flavus is associated with a higher genetic diversity in outbreaks compared to A. fumigatus. A. flavus is a major producer of aflatoxins and other mycotoxins, and it can cause a wide range of human diseases, including keratitis, cutaneous infections, wound infections, endocarditis, pericarditis, and central nervous system infections. It is also a common cause of allergic fungal sinusitis and sinus aspergilloma. A. flavus is more virulent and resistant to antifungal drugs than many other Aspergillus species. Recent genomic studies may help better understand its pathogenesis, toxin production, and allergens.