One third of the world's population lacks regular access to essential medicines partly because of the high cost of medicines. In Vietnam, the cost to patients of medicines was 47 times the international reference price for originator brands and 11 times the price for generic equivalents in the public sector. In this article, we report the results of a qualitative study conducted to identify the principal reasons for inflated medicine prices in Vietnam.Between April 2008 and December 2009, 29 semi-structured interviews were conducted with staff from pharmaceutical companies, private pharmacies, the Ministry of Health, and the Ministry of Finance of Vietnam. Study participants were recruited using a combination of purposive and snowball sampling techniques. Interviews were recorded, transcribed and coded using NVivo8® software and analyzed using a framework of structure-conduct-performance (SCP).Participants attributed high prices of originator medicines to a monopoly of supply. The prices of generic medicines were also considered to be excessive, reportedly due to the need to recoup the cost of financial inducements paid to prescribers and procurement officers. These inducements constituted a dominant cost component of the end price of generic medicines. Poor market intelligence about current world prices, as well as failure to achieve economies of scale because of unwarranted duplication in pharmaceutical production and distribution system were also factors contributing to high prices. This was reported to be further compounded by multiple layers in the supply chain and unregulated retail mark-ups.To address these problems a multifaceted approach is needed encompassing policy and legislative responses. Policy options include establishing effective monitoring of medicine quality assurance, procurement, distribution and use. Rationalization of the domestic pharmaceutical production and distribution system to achieve economies of scale is also required. Appropriate legal responses include collaborations with the justice and law enforcement sectors to enforce existing laws.