Oxalic acid (OA) is inhibitory to many fungal plant pathogens. To further characterize the molecular mechanism of OA involved in fungal pathogenesis, OA insensitive mutants were screened from a chemical inducible Arabidopsis mutant library (about 6000 lines) using MS medium (calcium free) containing 1.2 mmol/L OA and 10 micromol/L estradiol. Harvested putative mutants were collected separately. Individual lines of mutants were screened again on modified MS medium containing OA. Mutants D33, D74, D154, D282 and D630 with enhanced OA resistance were obtained. The T-DNA flanking sequences were amplified by TAIL-PCR. The sequences were blasted against TAIR database. The result indicated that the T-DNA of mutant D33 was inserted between At2g39720 (zinc finger) and At2g39730 (Rubisco activase), and the T-DNA junctions of the other four mutants were the same, all inserted in the same site of the first intron of At5g10450 (14-3-3 protein GF14 lambda).