[Background] Mycotoxins produced by different species of fungi may coexist in single cereal or feed samples, which could become highly toxic for humans and animals. In this context, a dual flow immunochromatographic assay for rapid monitoring mixed mycotoxin contamination has become a necessity. [Objective] Development of the colloidal gold dual immunoassay for simultaneous detection of ochratoxin A and zearalenone in cereal and feed samples. [Methods] Mycotoxins monoclonal antibodies were labeled with colloidal gold nanoparticles. After optimizing the materials, reagents as well as the experimental conditions, a dual flow immunochromatographic assay was developed and tested for determining the ochratoxin A and zearalenone in cereal and feed samples. [Results] The detection limit for ochratoxin A and zearalenone was 0.625 ng/mL and 1.25 ng/mL, respectively. Naturally contaminated cereal and feed samples were analyzed using both immunochromatographic assay and LC-MS/MS, and showed a good agreement between these two methods. [Conclusion] This immunoassay could detect ochratoxin A and zearalenone in cereal and feed samples rapidly and accurately, more easily and at a lower cost.