Banking industry is a crucial industry in the Sri Lankan economy. With the development of technology, the self-banking concept has been introduced in the island and it has now become an integral part to both customers as well as the banking institutions. Therefore, this study focused on the determinants of the technology based self-banking system in Sri Lanka. The main objective of the study was to identify whether usefulness, ease of use, risk and contribution of banking institutions can be a determinant on the adoption of the self-banking system in Sri Lanka. This research tries to make an extension to the Technology Acceptance Model introduced by Davis, (1989). The quantitative data were gathered using a structured questionnaire and the sample size was 164. Cluster sampling was used. Univariate, bivariate and multivariate analytical methods were applied to analyze the data. The findings of the study revealed that there was a moderately high level of self-banking adoption. Furthermore, there is a significantly strong positive relationship between perceived usefulness and perceived ease of use with the adoption of self-banking, while the risk and contribution of banking institutions imply a weak positive relationship with the adoption of self-banking. On one hand, the Multiple regression analysis recognized that perceived usefulness and perceived ease of use are significant determinants for the adoption of self-banking. On the other hand, the risk and contribution of banking institutions do not determine cause of adoption of self-banking. Moreover, usefulness determines the increment in the adoption level of customers more than the ease of use. According to the results of the study, it can be suggested to the banking authorities to build and maintain self-banking technologies in a way that they would increase the usefulness to the customers.   Keywords: Self-banking, Self-service banking, Technology Acceptance Model