By converting the normal distribution function into histograms having different ratios of rectangle width to standard deviation, correction factors are obtained which lead to a graphical method of evaluating gamma-ray photopeaks. Examples of the method are given and its limitations are discussed. The quantitative analysis of a gamma-ray spectrum begins with an estimation of the number of photons of a given energy which lose all of that energy in the detector. The methods of making this estimation range from simple “eyeball” techniques to algebraic solutions requiring the application of digital computers. The method described here provides a simple but accurate technique based on a theoretical analysis of the normal distribution function. It is similar in many respects to the methods described by BOEKELHEIDE and by ZIMMERMAN, but has certain advantages over both these of (see Discussion).