© 2020 Kitajima et al. Background As the Japanese population ages, the number of cancer patients will likely increase. Therefore, qualified cancer health care providers should be recruited and retained. Nurse job satisfaction is influenced by numerous factors and may affect staff turnover and patient outcomes. Objectives To evaluate the job satisfaction of certified nurses and nurse specialists in Japanese cancer care and elucidate factors associated with job satisfaction. Methods Participants in this cross-sectional study comprised 200 certified nurse specialists and 1,472 certified nurses working in Japanese cancer care. A chi-square test and logistic regression analysis were conducted to identify job satisfaction factors. Results Job satisfaction was present in 38.45% and 49.00% of certified nurses and nurse specialists, respectively. Certified nurses associated job satisfaction with cross-departmental activities (OR 2.24, p<0.001), positive evaluation from senior stuff (OR 4.58, p<0.001), appropriate staff allocation (OR 1.75, p<0.001), more than five years certified nurse experience (OR 1.91, p<0.001), and positive evaluation of the development of certified nurses (OR 2.13, p<0.01) and nurse specialists (OR 1.37, p<0.05). Low job satisfaction was associated with working on a ward (OR 0.51, p<0.001) and a capacity of more than 200 beds (OR 0.33, p = 0.00). Certified nurse specialists associated job satisfaction with palliative care team participation (OR 2.64, p<0.05), cross-sectional activities (OR 7.06, p<0.01), positive evaluation from senior stuff (OR 13.15, p<0.001), presence of certified nurses in radiation therapy (OR 2.91, p<0.05), positive certified nurse specialist development evaluation (OR 7.35, p<0.001), medical service fees (OR 3.78, p<0.01), and independent activities (OR 11.34, p<0.01). Conclusions We identified factors related to activities, facilities, and the cancer care team associated with job satisfaction of certified nurses and nurse specialists in Japanese cancer care. Suggestions are provided to enhance job satisfaction through Japan's Basic Plan to Promote Cancer Control, which may help hospital administrators retain nursing staff.