OBJECTIVE: Japan has recently implemented screening and support to balance cancer treatment and work. The present study evaluated whether the interest of employers in small and medium-sized enterprises (SMEs) affects cancer control in the workplace. METHODS: Cancer preparedness at work was examined by a Japanese life insurance company contracting 370 000 SMEs. The analysis targeted SMEs hiring ≤50 employees whose employer was aged ≥40 years. The endpoints were performing one or more screening for stomach, colon, or lung cancer recommended for both sexes in Japan and implementing three or more supportive measures from the nine systems listed in a questionnaire. Logistic regression analysis was performed to predict these endpoints using other factors. RESULTS: The survey was completed from January 5 to 28, 2022 and included 5268 eligible companies. Around half were small enterprises with up to five employees. Screenings were performed for stomach (32%), colorectal (27%), and lung (26%) cancers. Sick leave (36%) was the most common support for balancing cancer treatment and work. Logistic regression analysis revealed that employer's concern was a significant predictor of screening (odds ratio [OR] = 3.59, P < .001) and support (OR = 2.55, P < .01) compared with "not concerned at all," along with industry type, annual sales, experience of employees with cancer, and employer's participation in screening. CONCLUSION: Our findings suggested that employers' interest was a powerful predictor of implementing cancer control in SMEs. Educational intervention targeted toward the employer could play a critical role in improving SMEs.