This paper examines issues of democratic transition, legal reform and customary law, focusing on the case of Guatemala. The Accord on the Identity and Rights of Indigenous Peoples, signed by the Guatemalan government and the URNG (Unidad Revolucionaria Nacional Guatemalteca) in March 1995 as part of the peace process, commits the government to incorporating the customary law of the country’s indigenous Maya population into the design of the state via legal reforms. Here the importance of customary law for democratic transition in Guatemala is emphasised and a critical perspective for its study and analysis in this context developed. The second half of the paper presents preliminary results of a study in the department of Alta Verapaz applying the methodological approach proposed here.