The genetic diversity of traditional food crops is rapidly declining in the Pacific Islands, as is also true globally. This loss in the Pacific is of particular concern worldwide because some of these islands (such as New Guinea) are primary centres of origin of several globally important food crops (e.g. bananas and sugar cane). This article provides background information on the evolution of the diversity of these crops, investigates (within the Pacific context) the socioeconomic reasons for this loss, analyses its possible economic consequences, and considers the economic benefits and costs of conserving crop varieties. The potential economic benefits foregone by failing to conserve a crop variety that possesses genetic attributes which would counter a productivity reducing new disease or environmental development is shown to depend on the nature of the demand function for the crop’s production. Other things being held constant, this potential loss is greater the larger is the absolute demand for a crop’s production and the more inelastic is this demand. Staple crop’s production seem to satisfy these conditions, especially the first one. In fact, gene banks in the Pacific Islands have concentrated on conserving varieties of staple crops. However, ignoring the conservation of minor traditional crops may not always be optimal, given that circumstances change. The economics and costs associated with the conservation of crop diversity in situ and ex situ are discussed. The effective analysis of this is shown to be challenging but it is an important consideration in making conservation decisions. Unfortunately, this subject appears to have received little attention in the Pacific as well as globally.