At this thesis, a novel sample preparation procedure by using molecularly imprinted polymer (MIP) as the solid phase extraction material for the preconcentration and determination of piroxicam (PX) and hydrochlorothiazide (HCT) in pharmaceutical samples has been developed. The performance conditions of a MIPs as a selective sorbent for the preconcentration of these drugs were studied. The MIP was synthesized by non-covalent method with PX and HCT as the template molecules, methacrylic acid as the functional monomer and the ethylene glycol dimethacrylate as the cross-linking monomer in the presence of dimethylformamide as the solvent. Under the optimum conditions, the PX and HCT in aqueous samples were separated and preconcentrated about 1000-fold by the SPE column. The detection limit for PX and HCT were 0.075, 0.073 ng/ml, respectively.