A new analysis procedure for determining formation flow capacity and skin factor from dug-test data is presented. The procedure arises from exact deconvolution equations that convert measured slug-test pressure data into equivalent pressure and pressure-derivative responses that would be obtained if the well were produced at a constant surface flow rate. The converted data then can be analyzed by use of existing wellbore-storage and skin type curves for the particular reservoir or well model represented by the field data. For cases where the slug test is short, we show that now rate convolution can be incorporated to improve analysis reliability. The analysis procedures do not require direct knowledge of the sandface flow rate.