This book is designed for the students of engineering, arts and science colleges of various universities in India. Also, this book will be a reference for practising engineers in industries. This book deals with 8086 microprocessor architectures, programming, interfacing with peripherals and application case studies. This book is organized with 9 chapters. The fundamental concepts of architecture and assembly language programming of 8086 microprocessor are presented in an easiest and elaborative manner. The assembly language programs are illustrated with problem analysis, algorithm and flowchart for better understanding. The assembly language program codes are run on assemblers with sample data and list file and results are also presented for clear understanding of the reader and also useful for laboratory exercises.