This paper presents a novel transportable and cost-effective Augmented Reality system developed to support interior design activities in the contract design sector. The main functioning principles and technical information about its implementation are provided to show how this system allows overcoming some of the issues related to the use of the Augmented Reality in interior design activities. The effectiveness of this system is verified through two different testing sessions based on a case study, which relates to the contract design sector. The testing sessions involved many interior designers with the intent of demonstrating the possibility of integrating this Augmented Reality system in the “everyday” interior design practice in the specific context of the contract design.