This work proposes an object oriented design method for Ada software. The mehod is mainly intended for software engineers who are not experts in object oriented design, in the context of a course as well as in the context of a firm wanting to acquire experience in object oriented design. To meet this objective, the method is simple and easy to learn. It also minimizes the risks of errors and it is possible to use it without resorting to complex tools in order to easily develop a small application. We will start by giving the basic concepts used in the method. Then we will describe the phases of the method. Finally, we will apply the method on a small example: a search tool for documents. The first phase is the software requirements phase in which the functions offered by the software are analysed and described in a software requirements specification. The second phase is the architectural design in which the components of the architecture are identified. The components identified are the objects and classes of the application, their structures, the associations between them, their attributes and the services they export. These components are described in an architectural design document. The third phase is the detailed design phase in which the components identified during the architectural design phase are described in detail. Among other things, the Ada mechanisms used to code the components are given. The results of this phase are a detailed design document and the Ada specifications of the objects and classes. Finally, the last phase is the implementation phase whose results are the listings of the code implementing objects and classes identified during the second phase.