Background: The annual rate for childhood cancers in developed countries amounts to 105–130 new cases per 1 million children. The Polish population aged 0–17 years is estimated at approximately
10 million children and adolescents, thus ca. 1100–1300 new cases can be expected every year. In 1995, we started a national childhood cancer registry.
Material/Methods: Information on the new diagnoses of childhood cancers was collected in 11 regional centers and submitted to the national center in Lublin. All data were verified carefully and standardized incidence rates were calculated.
Results: In 1995, we registered 1028 newly diagnosed malignant neoplasms, in 1996 and 1997 – 1036 cases, in 1998 – 1007, and in 1999 – 1158 new cases. The estimated incidence rates were: 102.4; 109.5; 111.9; 111.6 and 118.3 per 1 million children, respectively. The most frequent childhood cancers include leukemia, which accounts for 28% of cancer cases, lymphoma (14.3%) and C. N. S. tumors (16.3%).
Conclusions: Neoplasms of the hematopoietic system (leukemias and lymphomas) account for about 42% of all childhood cancers. Malignant lymphomas, bone tumors and germinal tumors are more frequently
diagnosed in Poland, but the incidence of central nervous system tumors is lower than in other countries.

Keywords: Adolescent, Child, Child, Preschool, Leukemia - epidemiology, Lymphoma - epidemiology, Neoplasms - epidemiology, Poland - epidemiology, Registries