We carried out a retrospective analysis on a series of 1743 plasma donors during the period from January 1999 to February 2004 to determine the frequency of monoclonal gammopathies occurrence. In the whole group, we observed 0.68% occurence and in the subgroup of donors over 40 years of age even 1.18% occurrence of the serum paraprotein. We have presented our recommendations for the screening of monoclonal gammopathies in blood donors.