Online surveys are unique in the fact that a researcher never knows how exactly the questionnaire is going to appear on a respondent’s screen because this is dependent on device, browser and personal settings. In addition, respondents use a range of different devices to complete surveys. Smartphones with Internet connection are very different in screen size and method of navigation (touchscreen) compared to regular desktop PCs. In this chapter we discuss the design of the survey instrument, such as the use of a paging or scrolling design and different types of answer formats available for online surveys. In addition, we discuss the actual fieldwork such as recruitment, data collection, and Internet-related issues related to processing of the data.