A diffusion technique is described that does not involve the usual long‐time approximation for a thin specimen. Activity measurements are programmed on a digital computer to generate a large number ofDvalues from the analysis of the data. TheseDvalues are then treated statistically, the resulting distribution curve yielding information on the experiment itself. The technique is fairly insensitive to errors in determining the scattering characteristics of the system or in taking the data.A version of this technique applied to Pb at 300°±2°C yielded average and rms values forD, the self‐diffusion coefficient, of 1.78±0.15×10−10cm2/sec and 1.92±0.16×10−10cm2/sec, respectively, from 40Dvalues generated from the data. The results compare favorably with the published data on self‐diffusion in Pb at 301°C by von Hevesy, 1.85×10−10cm2/sec. The data were also treated according to a long‐time approximation method of Zhukhovitsky, yielding 1.70×10−10cm2/sec.