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Picloram is an auxinic herbicide that is widely used for controlling broad leaf weeds. However, its mechanism of transport into plants is poorly understood. In a genetic screen for picloram resistance, we identified three Arabidopsis mutant alleles ofPIC30(PICLORAM RESISTANT30) that are specifically resistant to picolinates, but not to other auxins.PIC30is a previously uncharacterized gene that encodes a major facilitator superfamily (MFS) transporter. Similar to most members of MFS, PIC30 contains 12 putative transmembrane domains, and PIC30‐GFP fusion protein selectively localizes to the plasma membrane.In plantatransport assays demonstrate that PIC30 specifically transports picloram, but not indole‐3‐acetic acid (IAA). Functional analysis ofXenopus laevisoocytes injected with PIC30 cRNA demonstrated PIC30 mediated transport of picloram and several anions, including nitrate and chloride. Consistent with these roles of PIC30, three allelicpic30mutants are selectively insensitive to picolinate herbicides, whilepic30‐3is also defective in chlorate (analogue of nitrate) transport and also shows reduced uptake of. Overexpression ofPIC30fully complements both picloram and chlorate insensitive phenotypes ofpic30‐3. Despite the continued use of picloram as an herbicide, a transporter for picloram was not known until now. This work provides insight into the mechanisms of plant resistance to picolinate herbicides and also shed light on the possible endogenous function of PIC30 protein.