Several surface plasmon resonance (SPR) biosensor assays were developed and validated for the detection of anthelmintic veterinary drugs in liver tissue and milk using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction procedure. The first screening assay was developed to detect 11 benzimidazole carbamates in milk and liver. In bovine milk the assay showed a limit of detection (LOD) of 2.7 μg kg-1 and a detection capability (CCβ) of 5 μg kg-1. Analyte recovery was in the range 81 to 116% and the assay was found to be fit for purpose when its performance was compared to UPLC-MS/MS analyses of milk from cows treated with benzimidazole products. In bovine liver the LOD (32 μg kg-1) and the CCβ (50 μg kg-1) were determined and the analyte recovery was in the range 77-132%. All non-compliant samples were identified when the assay performance was tested by analysing liver from animals treated with benzimidazole drugs and comparing the results with a UPLC-MS/MS confirmatory method. A screening assay was developed for four amino-benzimidazoles in liver. The LOD (41 μg kg-1) and the CCβ (75 μg kg-1) were determined and the analyte recovery was in the range 103-116%. A screening assay for thiabendazole and 5-hydroxy-thiabendazole in ovine liver tissue using a novel recombinant antibody fragment (Fab) was developed. The LOD (12.3 μg kg-1), the CCβ (20 μg kg-1) and analyte recovery (86-107%) satisfied the criteria required for thiabendazole screening in liver tissue. A biosensor to detect triclabendazole residues in liver tissue was developed through the immobilization of amino-triclabendazole via a glutaraldehyde homo-bifunctional crosslinker. Several experiments were required to reduce non-specific binding in this assay. An LOD of 105 μg kg-1 was determined which was close to the maximum residue limit (MRL) in liver matrix (100 μg kg-1).A biochip array was developed and validated to screen orange juice for fungicide and pesticide residues. The LOD for carbendazim (20 μg kg-1), 2-aminobenzimidazole (4.0 μg kg-1), thiabendazole (4.2 μg kg-1) and ivermectin (10.2 μg kg-1) residues were determined. The CCβ for carbendazim (50 μg kg-1), 2-aminobenzimidazole (10 μg kg- 1), thiabendazole (10 μg kg-1) and ivermectin (20 μg kg-1) residues were sufficient for the analysis of orange juice. When orange juice from retail outlets in the greater Dublin area (n = 15) Two samples contained thiabendazole residues above the CCβ (260 and 181 μg kg-1) however these concentrations were below the maximum residue limit.