Background: Cancer screening rates in Japan are much lower than those in Western countries. This studyevaluated the relationship between cancer screening rates and strategies used to improve screening rates, anddetermined which strategy is the most effective. Materials and Methods: All municipalities are responsible forconducting gastric, lung, colorectal, cervical, and breast cancer screenings in Japan. Of the 1,746 municipalitiesin total, 92-99% were included in the analyses for each cancer screening. Using national data in 2009, thecorrelations between cancer screening rates and strategies for improving screening rates of all municipalities,both large (populations of over 30,000) and small (populations of under 30,000), were determined. The strategiesused were as follows: sending personal invitation letters, personal visits by community health workers, use of aclinical setting for screening, and free screening. Results: Of all four strategies used to improve cancer screeningrates, sending personal invitation letters had the highest correlations with all screening rates, with the exceptionof breast cancer screening. The partial correlation coefficients linking this strategy with the screening ratesin all municipalities were 0.28, 0.32, 0.30, and 0.26 for gastric, lung, colorectal, and cervical cancer screening,respectively. In large municipalities, the correlations between the number of examinees in a clinical setting andthe screening rates were also relatively high, particularly for cervical cancer screening (r=0.41). Conclusions:Sending personal invitation letters appears to be particularly effective in improving cancer screening rates inall municipalities. All municipalities should implement a system that sends personal invitation letters for cancerscreening. In large municipalities, increasing the availability of screening in a clinical setting is also effective inimproving cancer screening rates.