The main subject of this thesis is the analysis of modern threats posed by computer fraud in the financial sector, particularly in banking. The digitalization of financial services has brought advantages in terms of accessibility for users but has simultaneously created opportunities for sophisticated cyberattacks. The paper covers the theoretical framework of computer fraud, the differences between computer crime and cybercrime, as well as the legal regulations in Croatia and the European Union. It also discusses the types of computer fraud in banking, including phishing attacks, malicious software, social engineering, ransomware, and DDoS attacks. Additionally, the financial consequences and the negative impact of the COVID-19 pandemic on the rise of cybercrime are examined. This thesis analyzes specific cases of computer fraud that demonstrate the vulnerability of banking systems to new and sophisticated attacks. It proposes preventive measures and security strategies to protect banking systems, including multi-factor authentication, data encryption, artificial intelligence systems for transaction analysis, user security education, and the development of new technologies such as blockchain and quantum cryptography. The emphasis is on the importance of the continuous adaptation of financial institutions, the need to enhance legal and technological protection mechanisms, and the education of employees.