The objective of this paper is to examine value chain governance through case studies of four different certified value chains for Tanzanian tea. This paper takes a look at a traditional export commodity, tea, and discusses the implications of involvement in value-based certification schemes (Ethical Trading Initiative, Fairtrade, Organic and Rainforest Alliance) on certified producers in Tanzania. Each of these certification schemes makes claims on specific values that it is instilling in a particular â 'value chain'. This paper specifically analyses the network construction of each certified value chain and answers the questions: 1) which actors are involved in each value chain, 2) which values are claimed as organizing principles of these value chains, and 3) what does this mix of actors and values contribute to our understanding of value chain governance. Between 2008 and 2010, eighty in-depth interviews were conducted with stakeholders who are certified against sustainability standards. Twenty-one focus groups were formed comprising certified smallholders and hired labourers. The conclusions suggest that despite claims about the ability to change trading relationships through the certification systems, most of the old networks are still in place. The certification systems only add additional buyers to global value chains that were already governed by highly relational and hierarchical mechanisms. These conclusions thus place in question some of the claims made by certification bodies as to their abilities to change practices.