This two-volume set LNCS 10305 and LNCS 10306 constitutes the refereed proceedings of the 15th International Work-Conference on Artificial Neural Networks, IWANN 2019, held at Gran Canaria, Spain, in June 2019.The 150 revised full papers presented in this two-volume set were carefully reviewed and selected from 210 submissions. The papers are organized in topical sections on machine learning in weather observation and forecasting, computational intelligence methods for time series, human activity recognition, new and future tendencies in brain-computer interface systems, random-weights neural networks, pattern recognition, deep learning and natural language processing, software testing and intelligent systems, data-driven intelligent transportation systems, deep learning models in healthcare and biomedicine, deep learning beyond convolution, artificial neural network for biomedical image processing, machine learning in vision and robotics, system identification, process control, and manufacturing, image and signal processing, soft computing, mathematics for neural networks, internet modeling, communication and networking, expert systems, evolutionary and genetic algorithms, advances in computational intelligence, computational biology and bioinformatics.