This thesis presents the work based on the software cost estimation model COCOMO II, which was applied to a case study object derived from a software organization that had a completed project at its disposal. One of the most difficult phases in software development is the planning process and the ability to provide accurate cost estimations for a project. A competitive market calls for delicate and strategic excellence in management issues such as project plans. While software estimations may by straightforward in perception it is intricate in actuality. COCOMO II is allegedly one of the top contenders for the number one tool to utilize in software cost estimations, based on available literature, and it is an important ingredient for managing software lines of business. The original model was initially published by Dr. Barry Boehm in 1981, but as the software field moved rapidly into newfangled processes and techniques, the need to cope with this evolutionary change resulted in a revised and novel edition of the model. The industry project subjected to this case study acts as a source of data for the model to use as input parameters, and this procedure is systematically explicated in a data collection exposition. Validation and application of parameters as well as the model is later on applied as a foundation for subsequent discussions. Characteristics such as calibration and prediction accuracy in the estimation model are moreover scrutinized in order to base farther conclusions on.