A strategy is presented for evaluation of treatment procedures for landfill leachate with emphasis on organic pollutants. An analytical scheme, the LAQUA protocol, was developed as a guide for the analytical work. The protocol includes organic as well as metals,. inorganic ions, water-quality parameters, and toxicity. The proposed strategy considers the behaviour of both polar and non-polar organic substances at trace levels. For polar substances, phenols were chosen as markers and determined with an automated supported liquid membrane extraction device, coupled on-line to HPLC with a diode-array detector. For non-polar substances, PCBs and 10 unidentified compounds were chosen as markers and analysed by solid-phase extraction combined with supercritical fluid extraction with GC analysis. The chosen measurement strategy, based on the use of marker substances, difference measurements, and versatile data-handling procedures, provided essential information about complex systems at relatively low cost.