A geostatistical conditional simulation routine that employs both parametric and nonparametric geostatistics is coupled to the pilot point inverse method to simulate the spatial distribution of conductivities in a dolomitic aquifer which is fractured in some areas and unfractured in others. An inversion is then conducted to obtain the conductivities within the fractured and nonfractured parts of the aquifer to match interference data from a series of three-dimensional pumping tests for an ensemble of 100 conditional simulations. The calibrated and predicted drawdowns match the observed drawdowns well. A comparison to the transmissivity interpreted from a single-well pumping test compared very well to the geometric mean transmissivity calculated from the calibrated realizations in this study. The results from this study indicate that conditioning the conductivity fields to the geologic facies data, in this case fractured-unfractured categorical data, as well as to ample transient hydraulic data can lead to robust groundwater flow models which can adequately predict the response to other hydraulic interference tests. ¿ 2001 American Geophysical Union