This document describes an online hotel booking system. The system allows users to check availability, book rooms, and manage reservations online through a website. It has two main modules: an administrator module that can manage customer and room details and update room status, and a user module that allows users to check availability, fill out reservation forms, and receive reservation confirmations. The system was developed using ASP.NET for the front end, SQL Server 2008 for the database, and C# and HTML/CSS for programming. Entity relationship diagrams and data flow diagrams are also included to show the database and system design.