In highly iterative development processes, functionality is continuously added while existing faults are repaired simultaneously. Therefore, practitioners need means to predict the fault inflow, i.e. the number of faults at the a certain project stage, in order to allocate resources adequately. This study investigates the use of software reliability growth models (SRGMs) for predicting fault inflow. Additionally, a simple linear model is developed and compared to the SRGMs. The paper provides results from applying these models on fault data from three different industrial projects. One of the key findings of this study is that SRGMs are applicable for predicting fault inflow in highly iterative processes. Moreover, the results show that a linear model provides reasonably accurate predictions as well and therefore, represents a valid alternative to the SRGMs.