A new short-term testing (STT) method is developed and presented in this paper. The STT method is based on a new semi-theoretical analytical solution of the diffusivity equation for a cylindrical source and is used to describe the transient buildup or drawdown pressures for stimulated wells. This solution gives a good agreement with the results of a numerical ("exact") solution of the diffusivity equation. The analytical solution allows us to determine the bottomhole pressure (or pressure derivative) at linear flow and linear-to-radial flow transition with high accuracy. For small values of time, the STT method gives a half-unit slope straight line (dimensionless pressure drop is proportional to the square root of time), and for large values of time, the conventional equation for a radial flow can be obtained. The STT method can be used for any values of flowing or shut-in time. For this reason, the principle of superposition can be used without any limitations. In the following, we demonstrate application of the STT method for two acidized oil wells.