The aim of this article was to examine and quantify 1) the dependence of additional purchases of banking products from customer loyalty and

2) dependence of bank clients’ loyalty from their satisfaction with the bank’s customer service. The respondents from our research in 2014 were divided into satisfied (loyal) and dissatisfied (disloyal) banking clients. Their attitudes in the area of loyalty and additional purchases of banking products were compared. Differences in attitudes were examined by means of Pearson statistics. It was found that satisfied customers were significantly more likely to recommend their bank to their friends, they often considered that they would use their bank in the future and they were more resistant to offers from other banks. Loyal customers are more interested in the services of their own banks when considering investments in the financial market, keep their savings in their own bank, take out mortgage loans from their own bank and use other banking products and services offered by their own bank the intensity of customer loyalty reflects the likelihood that customers will purchase additional banking products. According to the results of our research, with the different intensities the loyalty of customers is transforming into a potential purchase of additional banking products. The greatest potential interest of the bank customers was in keeping their own savings in the bank and mortgage loans. The intensity of interest in the purchase of financial investments and other products was relatively low