History and Objectives: German beetles are the most common beetles in human dwellings. They show different sensitivity to insecticides according to the region. Therefore, for determination for their sensitivity, they were collected from Naghavi, Shaheed Beheshti hospitals and Shabihkhani maternity hospital and exposed to different insecticides during the years 1995-1996.

Materials and Methods: Beetles were collected by hand or by putting trap. After 48h of their capture in laboratory according to standards of WHO, they were exposed to Ectelic (0.12 g/m² and 0.2 g/m²), Sulfak (0.2 g/m²), Kupex (0.125 g/m² and 0.25 g/m²) and Ficam (0.24 g/m²) and knock down experiments. In this study regression analysis and criteria KT50 and KT90 were calculated.

Results: For Ectelic insecticide (0.12 g/m²), a mortality of 45%, 53% and 65% was obtained in Naghavi, Shaheed Beheshti hospitals and Shabihkhani maternity hospital respectively. For Sulfak insecticide (0.2 g/m²), KT50 was 9.87. 6.72 and 5.51 min in Naghavi, Shaheed Beheshti hospitals and Shabihkhani maternity hospital respectively. For Kupex insecticide (0.12 g/m²), KT50 was 23.9, 9.93 and 7.89 min in Naghavi, Shaheed Beheshti hospital and Shabihkhani maternity hospital respectively. And for Ficam (0.24 g/m²). KT50 was 31.23, 14.98 and 16.20 min in Naghavi, Shaheed Beheshti hospitals and Shabihkhani maternity hospital respectively. For Ectelic and Kupex insecticides, there was not a 100% mortality rate after 24h and with a higher dose of Ectelic, mortality rate was 74%, 80% and 88% in Naghavi, Shaheed Beheshti hospitals and Shabihkhani maternity hospital respectively. For Kupex (0.25 g/m²), mortality was 100%.

Conclusion: It is concluded that sensitivity of beetles is different to different insecticides and also according to the site of collection. Multiple and repetitive use of these insecticides can lead to increased resistance.