The aim of this thesis was to devolp, accurate, sensitive and precise analytical methods for the analysis of certain drugs affecting circulatory system, namely; Betahistine dihydrochloride (BH), Hydrochlorothiazide (HCT), Xipamide (XIP), Valsartan (VAL), Minoxidil (MIN), Heptaminol hydrochloride (HEP), Triamtrene (TRM), Cinnarizine (CIN), Nicergoline (NIC) and Domperidone (DOM). The work included a spectrophotometric method for the determination of hydrochlorothiazide and minoxidil in pharmaceutical preparations and biological fluids through substitution reaction using 4- Chloro-7-nitrobenzofurazan (NBD-Cl). It also included spectrophotometric method for the determination of (cinnarizine, nicergoline) and (cinnarizine, domperidone) in pharmaceutical dosage forms through ratio difference, mean centering and dual wavelength methods. Green RP-HPLC method was developed for determination of valsartan and hydrochlorothiazide in pharmaceutical formulations. A micellar RP-HPLC method with UV detection was developed for determination of xipamide and triamterene in tablet formulations. At last a conductmetric method for determination of betahistine dihydrochloride, heptaminol hydrochloride using silver nitrate in pharmaceutical preparations was described.