Honey bees are exposed to agrochemicals such as insecticides, fungicides, herbicides, and spray adjuvants while foraging on treated crops. Fungicides have traditionally been considered bee-safe as they are designed to target the basic biochemical processes of fungal cells, but recent studies have suggested that they can cause death and, at lower concentrations, sublethal effects on bee behavior and physiology. Here, we focus on the fungicide Pristine^® (active ingredients: 25.2% boscalid, 12.8% pyraclostrobin), which is sprayed during the blooming period on a variety of crops, and is known to poison honey bee mitochondria at ppm levels. We tested whether chronic consumption of pollen containing Pristine^®, at a range of field-relevant and higher concentrations, impairs olfactory associative learning in honey bees. Learning performance was reduced at higher but not lower Pristine^® doses, with negative impacts occurring within the higher range of concentrations measured in the field. We next exposed bees to Pristine^® at larval, adult, or both life stages. We found that significant suppression of learning performance occurred when bees were exposed during both larval and adult life stages, and non-significant reductions occurred when they were exposed during only one stage. The reductions in learning could not be explained by effects on hunger or motivation, as sucrose responsiveness was not affected by Pristine^® exposure. Our study provides strong evidence that Pristine^® impairs olfactory learning, potentially affecting the foraging and pollination capacities of bees and raising renewed concern that standard methods to test the toxicity of agrochemicals to pollinators may need to be reevaluated. Supported by USDA-2017-68004-26322.