Detection of mutations in families with a hereditary predisposition to colon cancer gives an opportunity to precisely define the high-risk group. 36 patients operated on for colon cancer, with familiar prevalence of this malignancy, were investigated using the DNA microarrays method with the potential detection of 170 mutations in MLH1, MSH2, MSH6, CHEK2, and NOD2 genes. In microarrays analysis of DNA in 9 patients (25% of the investigated group), 6 different mutations were found. The effectiveness of genetic screening using the microarray method is comparable to the effectiveness of other, much more expensive and time-consuming methods.