The direct determination of pesticides adsorbed on solid-phase extraction (SPE) membranes by matrix-assisted laser desorption/ionization (MALDI) combined with quadrupole ion trap mass spectrometry is reported. Ionization was carried out in an external source followed by injection of desorbed ions into the trap using an ion lens. Ion accumulation from multiple desorption events and tandem mass spectrometric procedures were used to enhance the sensitivity and selectivity of the analysis. The potential of the method for quantitative analysis is discussed.