The objective of this study was to examine childhood cancer incidence in proximity to nuclear power plants in Illinois. Cancer cases diagnosed among Illinois children 0 to 14 years old from 1986 through 2005 were included in the study. Standardized incidence ratio (SIR) was calculated for the geographic zones defined by the proximity to nuclear power plants. The results show that children living within 10 miles of any nuclear power plant did not have significant increase in incidence for leukemia (period 1986-1995: SIR = 0.85 [95% confidence interval, CI: 0.54-1.26]; period 1996-2005: 1.23 [0.91-1.64]), lymphomas [period 1986-1995: 1.38 [0.77-2.27]; period 1996-2005: 0.77 [0.37-1.42]), or other cancer sites. Neither did the children living 10 to 20 miles or 20 to 30 miles from any nuclear power plants. This study did not find any significant childhood cancer excess among children living near nuclear plants and did not observe any dose-response patterns.