In this work, analysis of some hypotensive, hypoglycemic drugs (Pioglitazone-HCl, metformin-HCl, atenolol, bisoprolol hemifumarate, carvedilol, hydrochlorothiazide, irbesartan, ramipril and sotalol HCl) were studied. The aim of this work is to develop, optimize and validate sensitive, precise and accurate methods for determination of the investigated drugs, either in pure form or in their pharmaceutical formulations with low cost depending on the availability of chemicals and equipments. The investigation includes usefulness of certain spectroscopic techniques including:, spectrophotometry, atomic absorption spectrometry and spectroflourimetry. High performance liquid chromatography technique was also applied. The thesis consists of five parts: Part I: It describes the theoretical background and literature review of the selected drugs on the reported methods for their determination and also chemical structure, physical properties and pharmacological actions of the cited drugs. Part II: It describes high performance liquid chromatographic determination of various drugs and it is divided into four chapters: Chapter (1): It describes an introduction about HPLC. Chapter (2): It describes RP-HPLC method for separation of pioglitazone-HCl and metformin-HCl on chromolith performance RP18e column, a relatively new packing material consisting of monolithic rods of highly porous silica. The obtained results were compared with those of the reference methods. Chapter (3): It describes a stability-indicating RP-HPLC method for determination of a mixture of carvedilol and hydrochlorothiazide in bulk powder and in tablets. The obtained results were compared with those of a reference methods. Chapter (4): It describes a stability-indicating RP-HPLC method for determination of sotalol hydrochloride in bulk powder and in tablets. The obtained results were compared with those of a reference methods. Part III: It demonstrates charge transfer reaction using NBD-Cl for the spectrophotometric and spectrofluorimetric determination of irbesartan and bisoprolol hemifumarate. Results obtained showed good agreement with those obtained by reference methods. Part IV: It demonstrates the oxidation reaction between N-bromosuccinimide (NBS) and the drugs followed by oxidation of metol by the unreacted amount of NBS and then the coupling between the oxidation product of metol and sulphanilic acid for spectrophotometric determination of pioglitazone-HCl, atenolol and bisoprolol hemifumarate. Results obtained were compared with those of the official methods. Part V: It describes complexation reactions and it is divided into three chapters: Chapter (1): It describes simple atomic absorption spectrometric and spectrophotometric method for determination of pioglitazone-HCl, carvedilol and ramipril in pure form or in pharmaceutical preparations through ion-pair complex formation reaction with bismuth tertaiodide complex. Results obtained were compared with those of the official and reference methods. Chapter (2): It is concerned with studying the spectrophotometric determination of pioglitazone-HCl and carvedilol through ion pair complex formation with fast green FCF and orange-G dyes. Results obtained were compared with those of the official and reference methods. Chapter (3): It is concerned with studying the spectrophotometric determination of irbesartan and bisoprolol hemifumarate through ion pair complex formation with bromocresol purple dye. Results obtained were compared with those of the official and reference methods.