Background: Competency is used to channel abilities into successful processes and is employed in the medical field. Globally, several laboratory competencies exist, but the job descriptions of Japanese medical laboratory scientists differ from those of other countries and little evidence-based information on novice medical laboratory scientist competency is available in Japan. This study clarified the competencies of novice medical laboratory scientists based on various expert opinions in Japan.Methods: The Delphi method was used to achieve an expert consensus on novice medical laboratory scientist competencies. We asked the participants to evaluate the importance of each item using the Likert scale and set 70% as the final consensus rate.Results: We obtained 106/400 (26.5%) and 95/106 (89.6%) responses from participants in rounds 1 and 2, respectively. Their professional experience mean +/- standard deviation was 32.4 +/- 6.0 years (range: 13-41). The average of each category consensus rate was > 99.1%. Ninety-five expert opinions converged and agreed that the competency comprised 8 categories and 54 items.Conclusions: The survey results revealed that novice medical laboratory scientists were expected to have relatively higher main laboratory skill competencies in the 'Preparation and analysis' category than in other categories. Nevertheless, competencies in other categories required basic skills. In addition, our competencies contained unique competencies compared with others due to their divergent roles and their environment. Further research is warranted to explore assessment tools by developing a competency scale, thereby helping clarify the differences between ability and correlated factors. The unique competencies scale can help assess the efficacy of educational programmes for Japanese medical laboratory scientists.