Several resistance-associated mutations have been previously documented in the house fly Musca domestica, an important sanitary pest of humans and animals world-wide. Sensitive detection of resistance is crucial for effective insecticide applications. We have developed simple PCR-RFLP assays for reliably detecting the G342A/V mutations in the acetylcholinesterase (Ace), the L1014F/H in voltage sensitive sodium channel (Vssc) and the W251L/S in the carboxylesterase (mdaE7). These accurate diagnostics are useful to monitor the frequency of the resistance mutations, thus, help to avoid ineffective insecticide application in fly control practice.