Although neural networks are applied in a wide range of learning and commercial applications even though this method is not commonly used for data mining tasks. Companies have been collecting data for decades and have build up massive data warehouses and used data mining techniques to extract the value of data but only few practitioners have used neural networks in data mining though this method has proven successful in many situations. The main academic contributions of this study are summarized as follows: (1) implementation of neural networks in analysis of marketing variables, (2) sensitivity analysis and variable reduction through weight analysis, and (3) showing how, by inclusion of Unknown, better results can be obtained from neural networks. Data mining is one of the booming application areas at the moment, and is an area where the operations researcher can find projects with industry. Neural network research is now being driven by industry, as more business problems are attempted and new research challenges emerge.