A method for evaluating partially resolved peaks is proposed, which consists of measuring the areas at both sides of the perpendicular through the minimum of the composite peak (e.g. using an electronic digital integrator), and multiplying these areas by appropriate correction factors to obtain the true areas of the two peak components. A set of such factors has been determined by numerical calculation, assuming Gaussian peak shapes. Parameters are two dimensionless quantities obtainable from the chromatogram which are characteristic of peak separation and peak area ratio, respectively. © 1969, Oxford University Press. All rights reserved.