Progress in preoperative chemotherapy and radiation therapy, both intra- and postoperative, has in time allowed for an increase in indications for shoulder implant surgery in malignant tumors, thus drastically reducing the number of amputations. The use of prostheses, particularly those of the more recent generation, respond to the needs to overcome the limits of loss of movement, as long as good anatomical reconstruction of the soft tissues, the premise for good functional and cosmetic recovery, is also possible. The current tendency is that of using modular shoulder prostheses that provide a wide variety of sizes. This type of prosthesis has surpassed custom made prostheses in terms of simplicity, adaptability and economy. The use of cementation in stabilization of the intramedullary stem has made them more stable even in the long term, allowing for early rehabilitation. The main problem in reconstruction with a prosthesis is the quantity of residual muscular tissue (deltoideus, extrarotators) and the stabilization system of the same to the prosthesis in order to avoid dislocation, which constitutes the main complication. It is the purpose of this study to present the clinical and functional results obtained in 23 implants carried out for primary malignant neoformation of the upper limb. The implants studied were of three types (custom made, modular in Cr-Co-Mb and Ti-Al-Va). The results reported show how a shoulder prosthesis can obtain good functional results, particularly when a part of the activator muscles of the shoulder such as the deltoideus and the extrarotators is preserved. When the contrary is true, the results obtained are modest because the prosthesis acts as a simple spacer.