The present study showed that treatment of stray dogs in captivity in order to prepare them for further experimental infection is not enough for elimination of parasites previously recorded in them. This phenomenon is not only related to the efficacy of the drugs used, but also for complete disinfection of places of captivity against infective stages of all included parasites. This study clears that after treatment of 2 groups of stray dogs captive in separate boxes by using Praziquantil      (1 Tablet/5-7kg B.W) and Fenbendazole (50 mg/kg B.W) revealed complete disappearance of Taenia sp. and Dipylidium caninum            (D. caninum) eggs and their gravid segments. Fenbendazole led to disappearance of previously diagnosed Ancylostoma caninum              (A. caninum) and Toxocara canis (T. canis) eggs at 2 weeks post treatment. Re-examination of captive dogs in floor pin 6 weeks post treatment revealed presence of T. canis, A. caninum, Taenia sp. and      D. caninum eggs by percentages of 9.09, 3.03, 6.06 and 6.06 % respectively in animals more than one year; while those less than one year showed incidence of T. canis, Taenia sp. and D. caninum with percentages of 16.67, 8.33 and 8.33 % respectively. On the other hand, re-examination of captive dogs in metal battery 6 weeks post treatment proved that there was no infection among them. This means that          re-infection took place as a result of the presence of intermediate host of    D. caninum, while reappearance of A. caninum and T. canis may be related to the presence of infective stages contaminating the media surrounding the treated dogs or presence of some migrating larvae that succeeded to escape from the applied treatment. This clears that the previous contamination in these boxes and their surroundings plays an important role in the re-infection of these animals by some parasites especially those depending on arthropod-intermediate hosts or those did not need intermediate hosts. In conclusion, this study denotes the importance of application of restricted measures to these boxes and their surrounding places together with prevention of arrival of other stray animals as well as rodents to these habitats.