Objective: To prepare and characterize Albumin microspheres of hydralazine hydrochloride for the treatment of hypertension. Methods: Albumin microspheres of antihypertensive drug hydralazine hydrochloride were prepared by emulsion cross-linking method by using glutaraldehyde as cross-linking agent. Drug and polymer compatibility was determined by Fourier-Transform Infrared spectroscopy. To determine the effect of polymer concentration and amount of glutaraldehyde, formulations were characterized for their entrapment efficiency, particle size, surface morphology and release behavior. In vivo study was carried out on hypertensive wistar rats. Key findings: Maximum percentage entrapment efficiency (%EE) was found to be 68.20±1.03 %. Laser particle size analyzer confirmed mean particle size in the range of 31.7 to 39.6μm. In vitro drug release studies showed a biphasic release pattern for all formulations with an initial burst effect followed by slow release for almost 24 hrs. Conclusion: In vivo study to determine antihypertensive effect of selected formulation strongly correlates with in vitro drug release behavior. The release behavior was significantly regulated by polymer concentration and volume of glutaraldehyde. The study revealed that hydralazine hydrochloride loaded albumin microspheres exhibited prolonged reduction of systolic and diastolic arterial pressure compared to hydralazine hydrochloride solution.