Wild animals and their derivatives are traded worldwide. Consequent poaching has been a main threat to species conservation. As current interventions and law enforcement cannot circumvent the resulting extinction of species, an alternative approach must be considered. It has been suggested that commercial breeding can keep the pressure off wild populations, referred to as wildlife farming. During this review, it is argued that wildlife farming can benefit species conservation only if the following criteria are met: (i) the legal products will form a substitute, and consumers show no preference for wild-caught animals; (ii) a substantial part of the demand is met, and the demand does not increase due to the legalized market; (iii) the legal products will be more cost-efficient, in order to combat the black market prices; (iv) wildlife farming does not rely on wild populations for re-stocking; (v) laundering of illegal products into the commercial trade is absent. For most species encountered in the wildlife trade, these criteria are unlikely to be met in reality and commercial breeding has the potential to have the opposite effect to what is desired for conservation. For some species, however, none of the criteria are violated, and wildlife farming can be considered a possible conservation tool as it may help to take the pressure off wild populations. For these species, future research should focus on the impact of legal products on the market dynamics, effective law enforcement that can prevent corruption, and wildlife forensics that enable the distinction between captive-bred and wild-caught species. Keywords: Wildlife trade, Wildlife farming, Commercial breeding, Rhino horn, Bear bile, Tiger bone, Pet trade, Species conservation.