Elongational flow measurements were performed on a number of samples under similar conditions using two different elongational rheometers, a Munstedt type oil bath rheometer (MTR) and the elongational viscosity fixture (EVF) of TA Instruments in an ARES rheometer. Deviations of several degrees from the set temperature are found in the case of the EVF/ARES and had to be corrected before comparing results. Inhomogeneous deformation, e.g. due to sagging, leads to an artificial strain‐hardening of the EVF. For strain‐hardening and/or high viscous materials a good agreement between measurements from both rheometers is found. The strain hardening measured in the EVF/ARES starts at smaller strains compared the MTR. This effect is more pronounced for weakly strain‐hardening materials. The possibility of creep and creep‐recovery experiments performed by the MTR demonstrates its wide application range.