I describe preliminary results for seasonal decomposition procedure using a modified Hodrick-Prescott (Leser) filter. The procedure is simpler to implement compared to two currently most popular seasonal decomposition procedures – X-11 filters developed by the U.S. Census Bureau and SEATS develop… ed by the Bank of Spain. A case study for Latvia's quarterly gross domestic product shows the procedure is able to extract a stable seasonal component, yet allowing for structural changes in seasonality.