The information age holds a number of daunting challenges for modern organizations, and more specifically, modern marketers. These challenges have contributed towards a fast-changing and more complex environment for organizations. This study examines the effect of E-marketing on the performance of the selected business organizations in Oyo State, Nigeria. The purposive method was used to select five manufacturing companies operating in Oyo State while the simple random sampling technique was used to select fifty respondents for the study. Data collected through structured questionnaire was analysed with the aid of Mean and Regression Analysis. Results of the analysis show that e-marketing has a significant impact on organizational performance measured by effective decision making, customer satisfaction and sakes volume.  The study also confirms that unstable power supply, lack of government support, low level of education of the owners/managers of business organizations and Security of documents through e-commerce are major threats to the success of e-marking adoption. The study concludes that the survival of business organizations, especially in this globally competitive environment, pivots on e-marketing. Subsequently, the study recommends that the government should provide enabling environment for e-commerce to triumph in Nigeria.  Also, management of Nigerian business organizations should establish e-marketing unit, administratively and financially separate and independent from marketing department, and give it a prominent place in the organizational structure, to be able to perform its functions without associating with the marketing management or other administrations in the company.