Investigations were conducted to determine the influence of selected pesticides on the growth of Rhizobium japonicum Kirch. Buch. in pure culture and in soil. In addition, nodulation and seed yield of inoculated soybeans [Glycine max (L.) Merr. cultivar ‘Wayne’] were studied under field conditions. Commercial formulations of 24 pesticides were screened for bacteriostatic activity on rhizobia using a gradient plate technique. Isopropyl m‐chlorocarbanilate (chlorpropham) and o,o‐diethyl‐s‐[2‐(ethylthio)‐ethyl] phosphorodithioate (disulfoton) were the only pesticides that inhibited growth. In addition to these pesticides, 4‐(methylsulfonyl)‐2,6‐dinitro‐N, N‐dipropylaniline (nitralin) and 1‐napthyl N‐methylcarbamate (carbaryl) were selected for further study to substantiate the laboratory results. Six U. S. Department of Agriculture rhizobia strains were cultured in pesticide‐amended medium 79 and subsequent growth was determined turbidimetrically. Nitralin exhibited little effect on the rhizobia, whereas chlorprophram, disulfoton, and carbaryl evoked a differential strain response. Most probable number determinations of pesticidetreated soil samples indicated that naturalized soil populations of R. japonicum remained unaltered four weeks after pesticide application. Recommended rates of the pesticides studied did not influence soybean nodulation or seed yield.