Results of the study of the role of suspended matter and its individual fractions differing in the size of their particles in the processes of accumulation and migration of metals (Al, Fe, Mn, Cr, Cu, and Mo) in lake ecosystems (on the example of Lake Nizhniy Telbin and Lake Verbnoye, Kiev) are given in the paper. It has been shown that in both lakes Al, Fe, Mn, and Cr migrate mainly in the suspended state. The mass contribution of the suspended form of each of the above-mentioned metals was as follows: in the water of Lake Nizhniy Telbin-77.7-86.6, 82.4-96.6, 45.6-56.9, and 29.9-74%, whereas in the water of Lake Verbnoye-43.8-68.4, 46.4-92.2, 30.5-70.4, and 0.7-93.4% of their total content in the water. At the same time, Cu and Mo were found mainly in the dissolved state: 66.6-74.9% Cu total and 63.9-77.8% Mo total in the water of Lake Nizhniy Telbin and 81.9-84.4% Cu total and 56.6-66.7% Mo total in the water of Lake Verbnoye. Data on the content of the studied metals in the composition of suspended matter fractions differing in the size of their particles (> 0.85 μm,> 0.40-0.85 μm, and> 0.23-0.40 μm) are also given in the paper. The contribution of metals in the composition of suspended matter fractions significantly increased with decreasing the size of the particles (in calculating in mg/g of suspended matter dry mass). A decrease in pH value to 4.0 resulted in the decrease in the contribution of the desorbed form of metals in the following order: Cr> Mn> Al> Fe, Cu regardless of the origin of suspended matter.