Technological modifications of food are being marketed as novel products that will enhance consumer choice and nutritional value. A recent manifestation is nanotechnology, entering the global food chain through food production, pesticides, vitamins, and food packaging. This article presents a detailed literature review on risk and benefit perceptions of technological developments for food and agriculture, including our own research from US deliberative workshops on nanotechnologies. The article suggests that many of the public concerns discussed in the literature on biotechnology in food are being raised in qualitative and quantitative studies on nanotechnologies for food: although nanotechnologies are generally perceived to be beneficial, many people express particular uneasiness about nanotechnological modifications of food. The article argues that these concerns represent material examples of unresolved social issues involving technologies and the food industry, including questions about the benefits of nanotechnology for food, and the heightened values attached to food as a cultural domain.