The present study presents an experimental and numerical investigation of single-phase pressure drop and heat transfer in a multipass cross-flow heat exchanger applied in a Rankine cycle for vehicle waste-heat recovery. A Rankine cycle experimental facility was used in order to obtain experimental pressure drop data, for adiabatic and diabatic conditions, and experimental Nusselt number data, using water as working fluid. A predictive pressure drop model was developed in order to obtain the working fluid pressure drop value in the heat exchanger under several operating conditions. Two different approaches were studied (a global and discretized approach) to compare the influence of temperature profile assumptions on the accuracy of the obtained pressure drop results. The heat transfer performance was assessed by the obtainment of the Nusselt number. The data reduction allowed to determine the Nusselt number by mean of the Wilson plot technic and compared with the existing correlations reviewed in the literature. The developed models were tested under a matrix of operating points which englobes adiabatic and diabatic conditions. The diabatic tests were conducted under tree different engine conditions: idle speed (1200 rpm), 2400 rpm and 2800 rpm, corresponding to exhaust gas thermal powers of: 0.75; 3.5 and 9 kW, respectively. These test conditions (including adiabatic conditions) resulted in a total of 68 different operating points, with a Reynolds number range of 51