Enhanced telecommunication technologies have enabled Taiwan government to provide businesses and citizens with integrated information and online services. Such technology-based services, often referred to e-government, have substantially advanced the efficiency and accessibility of public services. While the benefits of e-government are widely recognized, the use of online services remains low. The present quantitative study aims to uncover the underlying factors that influence business user adoption of e-government services. In particular, this study integrates the system acceptance model with the trust perspective to investigate the factors that influence business user intentions. Based on the results from questionnaires collected from 204 business users of an online tax payment system, the findings suggest that perceived ease of use has a positive impact on perceived usefulness, that structural assurance influences trust positively, that perceived usefulness, perceived ease of use, and trust have positive impact on attitude, and that trust and attitude influence behavioral intentions positively.