The study empirically examined the relationship between electronic payment system adoption and marketing success of Electricity Distribution Company in Port Harcourt, Nigeria. The population of this study comprises the customers of Electricity Distribution Company in Port Harcourt, Nigeria. There are 4,461,546 registered customers of Electricity Distribution Company in Port Harcourt (National Bureau of Statistics, NBS, 2025, www.nigerianstat.gov.ng). The researcher employed the Taro Yamen Formula to reduce the population to a reasonable sample size. The study has 4,461,546 customers of Electricity Distribution Company in Port Harcourt, which implies that the population of the study is known and cluster sampling technique, was therefore used to determine the sample size of 399 through the use of Taro Yamene’s formula. Multiple regression analysis was used with the aid of statistical package for social sciences (SPSS, version 21) analyze to the data. The study concludes that Based on the findings of the results, the study concludes that electronic payment system adoption strongly and positively relates with marketing success of electricity distribution companies in Port Harcourt as it creates a means of enhancing and increasing customer’s satisfaction which in-turn leads to customer loyalty. The study further recommends that, electricity distribution companies should ensure that e-wallet applications must always follow trends or developments in online consumer consumption patterns in Port Harcourt.