The Hebei Spirit oil spill (HSOS) occurred in the Republic of Korea on 7 December 2007. We aimed to describe the cancer incidence trend in Taean County before and after the oil spill. Five major cancers and leukemia were analyzed. Cancer incidence data were obtained from the Korean National Cancer Center. We compared the standardized incidence rates in Taean with those observed nationwide and selected three coastal areas. Joinpoint regression analysis was used to examine the trends in the average annual percent change and perform comparisons. The incidence rate of prostate cancer increased from 2007 to 2009 at an annual average of 39.3% (95% confidence interval (CI): −25.9, 161.8), 13.5% (95% CI: 11.7, 15.4), and 15.6% (95% CI: 11.9, 19.5), respectively, in Taean, nationwide, and in the coastal areas. The incidence of leukemia among women increased at an annual average of 9.5% (95% CI: −26.6, 63.4) in Taean and 0.6% (95% CI: 0.2, 0.9) nationwide; the rate decreased by 1.9% (95% CI: −12.8, 10.4) in the coastal areas. The trends between Taean County and the coastal areas differed only for prostate cancer (p = 0.0004). The incidence of prostate cancer among Taean County residents has increased since the HSOS.