We examine the possibility for precise determination of /V-ts/ (and /V-td/V-ts/) from the exclusive decays, B --> Kl(+)l(-), B --> K*l(+)l(-) (and B --> pi l(+)l(-), B --> rho l(+)l(-)). We show that the ratio /V-ts/ can be extracted experimentally with a small theoretical uncertainty from hadronic form-factors, if we appropriately constrain kinematical regions of q(2). We also give detailed analytical and numerical results on the differential decay width d Gamma(B --> K*l(+)l(-))/dq(2), and the ratios of integrated branching fractions, B(B --> rho l(+)l(-))/B(B --> K*l(+)l(-)). We estimate that one can determine the ratio /V-ts/ from those decays within theoretical accuracy of similar to 10%. (C) 1998 Elsevier Science B.V. All rights reserved.