Many, if not most, pesticides are not compatible with liquid fertilizers. The goal of the research presented in this paper was to develop a dispersant system that would allow the direct dilution of suspension-based agrochemical formulations into undiluted fertilizer. To evaluate the compatibility of dispersant systems with fertilizer, a series of surrogate fertilizers, based on ammonium phosphate solutions, was used with a variety of ionic strengths and pHs. Baseline performance was established with typical dispersant systems, and then a variety of electrolyte-tolerant surfactant systems was evaluated for improved compatibility performance. The most promising combinations of surfactants were evaluated in commercial fertilizer products of varying N-P-K (nitrogen-phosphorus-potassium) composition, pH, and micronutrients. A blend of surfactants was developed that shows robust compatibility with the set of commercial fertilizer products and compared favorably to a commercially available fertilizer-tolerant suspension.