This chapter provides a comprehensive overview of sampling methods for Internet-based surveys. It reviews the various types of sampling and sample designs; discusses their applicability to the different modes of Internet-based surveying; and, describes the techniques and practices for actually selecting Internet-based survey samples. Both probability and non-probability sampling methods for Internet-based surveys are described. Issues related to Internet-based survey sampling are discussed, including difficulties assembling sampling frames and in conducting probability sampling, undercoverage and coverage errors, and selection bias. The effects of the various sampling designs on statistical inference and analyses are summarized. The chapter broadly considers the uses of the Internet for surveying to include mixed mode surveys (particularly the combination of Internet-based surveys with more traditional modes) as well as the use of e-mail as a survey mode when other Internet-based methods are not available.