This book is part I of a two-volume work that contains the refereed proceedings of the 13th International Conference on Model Driven Engineering Languages and Systems, MODELS 2010, held in Oslo, Norway, during October 3-8, 2010. The 54 revised full papers presented were carefully reviewed and selected from 252 submissions. The papers are organized in topical sections on genericity and generalization, model migration and incremental manipulation, modeling model transformations, verifying consistency and conformance, taming modeling complexity, modeling user-system interaction, model-driven quality assurance, managing variability, multi-modeling approaches, distributed/embedded software development, (de)composition and refactoring, model change, (meta)models at runtime, requirements engineering, slicing and model transformations, incorporating quality concerns in MDD, model-driven engineering in practice, and modeling architecture.