The competition between organizations that develop software is increasing with the growth of the market in technology of the information, as consequence the organizations has concerned more and more with the improvement of the quality of itts products of software, with the effective costs and with the fulfillment of terms of its projects. To obtain these characteristics, the software development trials require a more effective management, with a well definite project plan based in accurate estimative. In that way, this work proposes through bibliographical hoist and field research, create a software estimative trial to support the management of projects during the cycle of development. This trial consists the use case points metric as a tool of estimative, in the estimative management trials proposed by the pmbok and in the estimative of development activities proposed by the rup. The results of the action research demonstrate that, in average, the software estimative trial with use case points is 4.3% more precise than the traditional estimative metrics (function points and use case points) without estimative formal trial.