Mass marketing also referred to as traditional marketing, has been criticised for trying to appeal to everyone, without necessarily providing for customers’ needs and wants. Therefore, the traditional marketing mix has been deemed ineffectual in a highly competitive and ever-changing business world, especially in the banking sector. Changes in the marketing environment have led to the development of new concepts such as relationship marketing. The fundamental concept of relationship marketing involves maximising the longterm benefits for the bank and the customer, resulting in a series of transactions, which allow a long-term relationship to be established and maintained. In short, it is a marketing concept that revolves around building and maintaining a long-term link or bond with one’s customers. The Zimbabwean banking sector has been affected by the country`s political and economic turmoil over the past decade. The collapse of the economy has affected the banking sector and its relationship with clients. During the economic crisis, Zimbabwean banks were unable to meet the basic international requirements of the Basel Accord, and as such, no profits were made. Borrowers had problems repaying existing loans; and banks also became reluctant to lend more, as a liquidity problem in the financial system was prominent. In 2009, a new government was formed which introduced the multi-currency system and the economy went on a recovery path. Given the nature of the economy of Zimbabwe, relationship marketing becomes an indispensible marketing tool that banks can use. The main purpose of the research was to investigate the relevance of relationship marketing on the sustainability of Zimbabwean banks. Five independent variables (customer relations, product attributes, promotion and service delivery and information technology) were identified and were tested against one dependent variable (sustainability of banks). A positivist research paradigm approach was used to conduct the research. The approach uses the quantitative method of research to establish causal relationships. Null (Ho) and alternative hypotheses (Ha) were formulated in x order to test the relationship between variables. A five point Likert scale questionnaire was developed and administered in five major commercial banks in Harare, Zimbabwe namey; Banc ABC, Barclays bank, Commercial Banks of Zimbabwe, Stanbic Bank and Standard Chartered Bank. The five major banks were selected in terms of market capitalisation as well as total deposit share among other things. The empirical results revealed that five of the independent variables positively correlated with the dependent variable implying that they all have an impact on bank sustainability. However, the current situation (2011) in Zimbabwe shows that only two independent variables (product variables and service delivery) have any impact on bank sustainability. In other words, there was a relationship between product attributes and sustainability of banks. Additionally, there was a relationship between service delivery and sustainability of Zimbabwean banks. Conclusions sited that product attributes and service delivery, as variables of relationship marketing, if implemented desirably could salvage the lost confidence and contribute to bank sustainability in Zimbabwe. Therefore, recommendations given by the researcher extensively focused on the two variables that have a relationship with Zimbabwean banks’ sustainability; briefly on the three variables (customer relations, promotion and information technology) that had no relationship.