The study purpose was to examine the influence of DNA isolation's method on result of genetic similarity analysis made by RAPD technique. Two methods od DNA isolation were used ? the Tomson-Henry method, which provides low purified DNA, and the column method, which provides high purified DNA. By using DNA isolated with these two methods the RAPD analysis of genetic distance was made. It was noticed, that using high purified DNA resulted in higher nu umber of amplification's products, and consequently in larger accuracy of analysis.