This thesis falls into three main chapters. Chapter I deals with a general survey of literature which discusses an introduction for chromium and vanadium (discovery, valances, uses, availability and toxic effects); also it includes the different techniques used for there determination. Focus was made on the determination of chromium and vanadium ions using spectrophotometric method in various different biological, industrial, drinking and sewage water samples. Chapter I also describes the aim of the research work conducted. Chapter II describes the preparation of chemicals and sample pretreatment. It also includes all the equipments used. Chapter III is divided into four parts (A, B, C and D) Part A: describes an integrated spectral study of complexes [(Cr (VI, III)-DPC), (Cr(VI)-bipy), (VO-SH), (V(V)-8-HQ)], it includes a study of the optimum conditions for the complex formation including the (determination of ligand concentration, effect of pH, determination of buffer concentration), also it includes a study of all the physical variables affecting the complex formation (time, temperature, light effect), and study of the nature of complexes following the continuous variation method. Part B: This part includes the preparation of calibration curves of the complexes and treatment data resulted by modern statistical analytical methods which involve different equation formulae for calculating linear regression equation, relative error, correlation coefficient, slop, intercept, and the theoretical limit of detection was also calculated. Part C: This part comprises two paragraphs: the first one includes a study of the effect of selected interfering positive and negative ions on the separation and determination processes. This effect is to explain thermodynamically by determining E1/2, Keq. and ?G values. The second paragraph includes a study of separating the interfering ions from chromium and vanadium ions using ion exchange columns. Part D: Describes the application of the method to determine chromium in the biological samples (blood and urine) and determine vanadium in plants and foods (mushrooms, strawberry and cereals) using the optimum conditions for determination.