That law is seeking for truth is certainly not new. However, proof and scientific expertise have received increasingly attention in the context of legal evidence. What are the relationship between scientific truth and legal evidence ? The aim of this paper is neither to assess the potential conflict between scientific truth and legal evidence, nor to measure in what extend scientific method might be applied to legal decision-making process. The paper is rather an attempt to point out some problems caused by scientific discoveries and technological advances in the context of legal evidence. Scientific progress is a chain of certainties and uncertainties. From their professional standpoint, lawyers and scientists have different understanding of truth, time and reality.