This book constitutes the proceedings of the 20th International Conference on Data Science, ICDATA 2024, held as part of the 2024 World Congress in Computer Science, Computer Engineering and Applied Computing, in Las Vegas, USA, during July 22 to July 25, 2024. This proceedings book includes 39 papers selected from a total of 243 submissions. They are organized in topical sections as follows: Artificial intelligence, data science, and neural networks; natural language processing, large language modelc, generative AI; data science, data analytics, and applications; prediction and forecasting and security applications; and poster papers.