We present the first example of a microfabricated PCR thermocycling chip integrated with advanced sample pre-treatment. The device consists of a SU-8 based PCR thermocycler chip monolithically integrated with dielectrophoretic (DEP) sample pre-treatment. This allows on chip purification of samples by removing inhibitors that would otherwise prevent PCR amplification. Integrated thin film heaters and a resistive temperature sensor control the PCR thermocycling. The sample pretreatment system uses a combination of fluid flow and cell capturing by DEP to perform the sample treatment. The sample pre-treatment system was tested on a sample containing yeast cells and heparin that inhibits PCR. Only treated sample could be successfully amplified using PCR.