Responsiveness to the requirements of the client and as accurate an estimate of duration of the project as possible are essential components of software development. Traditional software development methodologies are inappropriate for fast agile development, especially in small companies. The purpose of this work is to present the mergence of two agile software development methodologies applied to the case of a company to correspond with the new development process, and to give reasons for transferring to the new agile development method. This work begins with a presentation of the review and history of classic development methodologies, and continues with a detailed description of new agile development methodologies, especially Scrum and extreme programming. The last chapter concentrates on the merge of the two methodologies and their adaptation to the development of small companies.