Aquaculture holds considerable potential to contribute to poverty alleviation, if it provides poor people with opportunities other than as primary producers. Integration of aquaculture into poverty reduction programmes provides means to diversify production systems and reduce food insecurity but also needs improved markets in locations where aquaculture can o¡er sustainable livelihoods to poor farming households. This study reviews the current constraints that poor people face in accessing markets in Cambodia and analyses its implications for pro-poor domestic aquaculture development. We use a Geographic Information System-based spatial Bayesian probabilitymodel to simulate market accessibility and estimate the numbers of poor people who could potentially benefit from improved market access under four di¡erent scenarios. Analysis of secondary data confirms that the potential for poor aquaculture producers to interact with urban markets in Cambodia is currently low. The potential of aquaculture to interact with rural markets is, however, high. It is concluded that the development of aquaculture has considerable potential to reduce the transaction costs in domestic fish trade by improved access of poor producers and consumers to rural markets in Cambodia. An aquaculture development strategy that improves rural market access could include benefits for up to 1 million poor aquatic resource users.