The modes of distribution of the acid in a series of styrene/butadiene copolymer latexes prepared with varying concentrations of acrylic acid (AA) at a constant degree ot neutralization and with a constant concentration of AA at varying degrees of neutralization were estimated. A combination of methods was utilized for the distribution analyses. The concentration and apparent degree of neutralization of the acid in the polymer and aqueous phases of the latexes were determined from neutron activation analyses of oxygen and sodium in the latexes before and after their purification; the concentration of acid on the surface of the latex particles was determined directly from turbidimetric titration of the purified latexes with a cationic surface-active agent; and the concentration of acid "buried" within the latex particles was obtained from the differences between the neutron activation and turbidimetric titration results for the purified latexes. For latexes prepared with varying concentrations of AA, it was found that the ratio of the concentration of acid in the aqueous phase to that on the surface of the particles to that "buried" within the particles was usually a constant, approximately 2 : 3: 1. However, for latexes prepared with a constant concentration of AA, the concentration of acid within and on the surface of the particles was found to decrease strongly with increasing degree of neutralization of the acid used in the latex polymerization.