Challenges of data integration from multiple sources include inconsistencies in data formats, data quality issues, and discrepancies in data semantics. When merging data from diverse systems, organizations may encounter variations in naming conventions and measurement units. Additionally, ensuring real-time data synchronization can be complex, often requiring advanced ETL (Extract, Transform, Load) processes. Furthermore, compliance with data privacy regulations, such as GDPR, must be considered, adding to the complexity. Lastly, integration can involve significant resource investment for ongoing maintenance and updates, requiring skilled personnel and adequate technology infrastructure.