An experimental facility was constructed for post-harvest fog treatment of apple fruits stored in pallet-boxes. Its performance was tested by determining the distribution and effectiveness of fog application of the fungicide thiabendazole (TBZ) on wet and dry apples cv. Abbondanza . Deposition was greater on the upper (stalk end) than the lower (calyx end) part of the fruit but uniform between fruits in the pallet-box. The fog treatment was more effective against Phlyctaena vagabunda than the dip treatment; neither length of treatment nor pre-wetting of fruits substantially affected the distribution of TBZ fog deposit.The distribution and performance of the anti-oxidant diphenylamine (DPA) as fog on Stayman red apples was also tested. As with TBZ deposit on cv. Abbondanza , the DPA deposit was significantly greater on the top than the bottom of the fruit. Inversion of the pallet-box during fog treatment resulted in a more uniform deposit on fruit. Fog- and dip-treatment with DPA were equally effective in preventing superficial scald.