This study is an attempt to present experimentally the effect of poor thermal conductivity of thermoplastic on machining accuracy. In this case the machined surface roughness, maximum temperature generated during cutting and the dimensional accuracy of the drilled specimens were determined. The executed study shows that, the temperature generated increases by increasing the tool feed, cutting speed and hole depth. The use of large drill diameter leads to insignificantly increase the cutting temperature. The cutting speed during drilling teflon without cooling should not exceed 100 m min-1, if the temperature of the machined material is taken into account. At cooling with pressurized air, the drilling operation may be carried at speed up to 200 m min-1, since in this case the temperature generated in the cutting zone decreases approximately to 30-40°C. It is possible to drill holes with length equals twice the diameter at high speed and attain the desired accuracy.