Imidacloprid residues in plant material are typically determined by extraction of the sample in an organic solvent followed by analysis of the pesticide residue by either High Pressure Liquid Chromatography (HPLC) or by Gas Chromatography-Mass Spectrometry (GC-MS). These methods, while accurate, are expensive and time consuming to perform on large numbers of samples. An Enzyme Linked Immunosorbent Assay (ELISA) is commercially available which can analyze large numbers of samples with great sensitivity and at reduced cost. However, this assay is currently restricted to the determination of imidacloprid residues in ground and surface water samples. We attempted to develop a technique whereby the ELISA assay could be utilized to determine imidacloprid residues extracted from the leaves, wood, and bark of imidacloprid-treated maple and ash trees. Numerous solvent extraction schemes to remove the imidacloprid residues from the plant tissue were tested and the tolerance of the ELISA assay to these various extraction techniques is described. Imidacloprid was extracted both from laboratory spiked and field injected plant tissue. Residue levels obtained by tissue extractions were compared to imidacloprid levels in xylem sap squeezed from leaf bracts of the same trees.