Sweet potato is by far the most important staple food in Papua New Guinea. While much is consumed as a subsistence crop, it is also an important income earner for many small holder farmers in the Highlands of PNG. Of the Highlands sweet potato sold, about 90 percent is traded informally on open markets, locally or in coastal urban markets. Data from a consumer survey, from an informant interview of highlands suppliers and from consumer and supplier observations at the Lae market (the largest coastal urban market for sweet potato) was used to explore the extent to which Highland sweet potato in the coastal urban market of Lae, may be considered a differentiated product. As a staple food being sold on informal markets one may think it is best represented as an undifferentiated commodity. On the other hand, there are many different varieties as well as different offerings (e.g. heap sizes, washed/unwashed and Highland/Lowland) which suggest some product differentiation characteristics. Results suggest that consumer preferences in the Lae market are sophisticated and preferences are highly differentiated. It was also found that Highland suppliers do have some appreciation of the consumer preferences in the Lae market. However, it is also apparent that suppliers do not know how to differentiate their product to effectively meet demand and hence they are not very customer-responsive. The implications are that there is considerable potential to improve marketing strategy and management to take advantage of sophisticated consumer preferences.