An improved technique is presented to measure the normalized recombination strength Gat dislocations in silicon solar cells that were fabricated of cast grown silicon. G is the number ofrecombinations per unit time, length, and excess carrier density divided by the minority carrierdiffusion coefficient D. The measurement is based on fitting the theoretical correlation betweeninternal quantum efficiency IQE at a single wavelength and dislocation density r to the measureddata. The IQE is measured topographically by the light beam induced current (LBIC) method. Foreach point of the LBIC map a dislocation density is determined by analysing the etched samplesurface with an image recognition programme. The theory for IQE(r) combines Donolato'sprediction for L(r) with a calculation of IQE(L) made by the computer programme PC1D. L is thediffusion length of the minority carriers. The programme PC1D takes special properties of the solarcell process into account. The method was applied to solar cells made by a conventional furnaceprocess as well as a rapid thermal process (RTP). In the latter case a correlation between G and theemitter diffusion temperature was found. Finally TEM measurements were made to investigatedislocations with different values of G.