This research aims to determine how relations with customers affect the innovative activity of companies in AP Vojvodina, Serbia. Innovative activity means working on product innovations. Long-term partnership with customers, customer involvement in new product development and technology used in customer relations were used to analyse customer relations. The empirical research is based on a questionnaire, distributed to a sample of 31 companies in AP Vojvodina. Model creation and statistical analysis were done within the software package for statistical data analysis Smart PLS 4. The results showed that the development of long-term relationships with customers and the application of modern technology in relationships have a positive effect on product innovation. On the other hand, the influence of customer involvement in the development of a new product was not statistically significant when it comes to product innovation.