Background: For enhancing nursing education, we conducted concept synthesis and empirical validation of the essential genetic/genomic nursing competencies on cancer medicine for all nurses.　Methods: First, 41 articles were reviewed to produce a prototype concept of the essential genetic/genomic nursing competencies on cancer medicine (Study A). Second, focus group interviews were conducted with 21 standard-level nurses in cancer care, genetic/genomic nursing practices were extracted, and these were synthesized into Study A results. Consequently, although two new nursing practices were generated, analysis was terminated because no new concepts were created (Study B). Lastly, two experts performed empirical validation for all subjects.　Results: The following seven concepts were identified: "Utilization of genetic/genomic information," "Prevention of cancer including family members," "Adjustment of genome-related resources," "Attitude toward diversity in individuals," "Fulfillment of basic responsibilities," "Acquisition of specific medical knowledge," and "Awareness of the contribution of genetic/genomic medicine."　Discussion: Compared with the existing genetic nursing core competencies, cancer management systems and technological reforms have led to the addition of "administration management of molecularly targeted drugs" and "harmonization with organizational and regional policies." Thus, the nursing practice behind the concept has shifted from the legally prescribed "medical treatment for injured and ill persons" to "assistance in medical care" involving family members. Others concepts included core competences of general genetic/genomic nursing similar to cancer care.