Despite scientific evidence is relatively new that comprises various forms of scientific result proffered to assist judges in determination of scientific or technical facts to the ingredients of a complex crime, regulation of its admissibility and how to handle scientific evidence in courtroom remain problematic. Accordingly, this study examines legal and practical issues associated with the admissibility of scientific criminal evidence in Ethiopia and its application in Bench- Sheko Zone. In exploring the admissibility of scientific criminal evidence, the researcher has used qualitative research approach based on constructive research paradigm; primarily and secondary sources of data are employed as research methods to address multiple issues involved in the study. For admissibility of scientific evidence in criminal trials, there are criteria to be considered. But, some rules of criminal evidence in Ethiopia are against the criteria for admissibility of such evidence. This study argues that, the term scientific evidence does not exist in Ethiopian laws and reference to other terms like expert, expert witness; indirect knowledge, indirect evidence, medical testimony or body samples should be consulted for some understanding of scientific evidence and its admissibility. In the practices of Bench- Sheko Zone, there are a growing tendency of admitting such evidence in criminal proceedings without assessing its relevancy, materiality, competency, reliability, and credibility. Not only judges but also other practitioners are not familiar with purpose, nature, forms and admissibility grounds of scientific evidence. Thus, this thesis recommended Ethiopia should take some lessons from advanced jurisprudence to tackle both legal and practical problems. The practices of the court which are contrary to scattered rules of evidence should be reconsidered. Some scattered rules of evidence contrary to the human rights part of the Constitution should be amended. Finally, it recommended that adequate training should be given for all legal practitioners and supportive staffs to understand the scattered rules of scientific criminal evidence and to act accordingly.