This volume presents the proceedings of the 21st International Symposium on Bioinformatics Research and Applications (ISBRA 2025), focusing on advancements in bioinformatics and computational biology. The symposium, held in Helsinki, Finland, gathered leading researchers, scientists, and industry professionals to share cutting-edge research and foster collaboration. This collection features 66 carefully reviewed full papers selected from 167 submissions, reflecting the latest developments and future directions in the field.

This volume represents a curated collection of the latest research presented at ISBRA 2025, offering insights into the current state and future trajectory of bioinformatics and computational biology. The rigorous selection process, with 66 papers chosen from 167 submissions, suggests a high standard of quality and relevance. The proceedings are expected to serve as a valuable resource for researchers and professionals seeking to stay abreast of significant developments and emerging trends in these rapidly evolving fields.