Acquisitions librarianship is a means of building library collections, and the basis of all library services. Ethics is the principles of conduct governing an individual or a group. Acquisitions procedures are burdensome, ordering is a sensitive job, related to money, and the relationships among acquisitions librarians, publishers, vendors, and other departments are very complicated. There fore, ethical issues of acquisitions are regarded as important and deserve exploring. The article mainly discusses ethical issues and right behaviors of acquisitions. At first, it describes the nature of acquisitions librarianship and the definition and content of professional ethics. Secondly, the Code of Ethics and Statement on Principles and Standards of Acquisitions Practice of American Library Association are introduced with details. Thirdly, some main ethical issues on selection of information resource, ordering, and gifts and exchange are investigated, and the right behaviors are also defined. Finally, some suggestions of acquisitions ethics are made for libraries in Taiwan.