Nowadays, planning and scheduling is critical for companies of any size. We use planning in order to know how much a product will cost, how much resources are needed, and when a product will be delivered. However, planning is difficult and plans are often wrong. The primary purpose of this study is to build a model that predicts the resolution time of incoming issue reports based on past issue report data. Moreover, additional goals of the research are to determine which existing approaches of resolution time prediction yield the highest levels of accuracy, and which features of issue reports are essential for prediction.