This paper outlines the main existing doctrinal tendencies about the proof, emphasizing its configuration as a fundamental right and its manifestation in comparative constitutional jurisprudence; then it continues to briefly analyze the elements that make up the right to evidence and its scope as a substantial element of due diligence, according to its intense development in Bolivian constitutional jurisprudence. Finally, some relevant jurisprudential lines are included about the review of the assessment of the evidence in the constitutional venue, as well as the justification and motivation of the resolutions as an element of the guarantee of due diligence, according to the recent jurisprudence established by the Plurinational Constitutional Court of Bolivia.