Four pesticides in wettable-powder formulations were supplied in their commercial packages from their manufactured company to evaluate the interaction effect between physico-chemical properties of these pesticides and their packages under tropical storage conditions (54±1°C) for three days compared with WHO and CIPAC storage, in glass container.                 The tested pesticides were : Metalaxyl + copper chloride 50 %, Benalaxyl + copper oxychloride 46 %, Dimethomorph + copper oxychloride 46 %, and Iminocataidin + trisbesulate 40 %; whereas the raw material of the tested packages were polyethylene (po), polyethylene inside aluminum (al/po), polyethylene inside paper (pa/po), and aluminum inside paper (pa/al). The studied physico-chemical properties were % foam, % suspensibility, wettability, and free acidity or alkalinity for tested pesticides, whereas conductivity, pH, surface tension and salinity were studied for spray solution of the same tested pesticides. The obtained results clearly show that, all tested  package caused bad effect for suspensibility % in both hard and soft water except (pa/po) package with Dimethomorph + copper oxychloride in hard water. So, they failed in suspensibility test at package storage since the  suspensibility percentage of these pesticides were less than 60 %, although they passed in this test at WHO glass storage. On the other hand, the effect of tested packages on foam % of tested pesticides was between no effect or improvement effect upwards of that stored in glass container, whereas aluminum package increased free alkalinity of tested pesticides when it combined with paper or polyethylene package.  Except of (po) package in case of Iminocataidin + trisbesulate, all tested packages showed slight improvement in wettability/second as comparing with glass container. On the other hand, all tested packages showed bad effect against one or more property of physico-chemical properties of tested pesticides spray solutions such as pH, conductivity and surface tension. pH value of spray solution of tested pesticides affected as resulting to storage in tested packages in three forms : a) increasing in pH without any effect on conductivity as shown in case of Iminocataidin + trisbesulate with (po) package. b) increasing in pH values in hard and soft water and conductivity in soft water only as shown with Benalaxyl + copper chloride with (pa/al) packages. and c) decreasing in pH values in hard and soft water and conductivity in soft water of Dimethomorph + copper oxychloride with (pa/po) package. (pa/po) and (pa/al) packages caused increase in surface tension of tested pesticides spray solution in hard and soft water with the first package and hard water only with the second. From above results, it could be concluded that, there are relationship between raw materials of packages that used in packing of wettable powder formulations under Egyptian pesticides market conditions and physico-chemical properties of this formulation. On the other hand, the test of suspensibility at WHO glass container is unsuitable, although the same pesticide passed this test at WHO glass container but failed in this test at commercial package, therefore this test and other tests should be carried out practically in the useful raw material package used for packing pesticides.