Introduction: A well organized and conducted program of cancer screening at the population level should be scientifically based, cost-effective at long term, and designed on the good practice examples. Appropriate diagnosis and treatment should be warranted by high rate of target population inclusion, while appropriate diagnosis and treatment should be warranted for those with positive findings. Aim: The aim is to present implementation of the national programs of early detection of breast and colon cancer in Croatia. Results: In the first cycle screening for breast cancer (since the end of 2006), a total of 720,981 women were invited for mammography, of which 58.5% presented for screening, with more than 1500 cases of breast cancer detected. A total of 808,913 tests were distributed for colon cancer screening from the end of 2007 to the beginning of 2010, of which only 19.9% were returned, 7.7% of these positive. Colonoscopy yielded 77.5% of pathologic findings, including 388 (5.99%) carcinomas, 2492 (38.46%) polyps, 1641 hemorrhoids and 998 diverticula. Conclusion: In Croatia, the public health service has made maximal use of all its resources in the national programs of early cancer detection. Great efforts and time, along with continuous education of all those involved in the program, have been invested in preparatory activities, organization and coordination of the program, contacts and collaboration with family physicians, specialist units, mass media, regional and local authorities, partnership with non-governmental societies, monitoring, evaluation and quality control.