Pointer aliasing analysis is used to determine if two object names containing dereferences and/or field selectors, (e.g., *p,q->t), may refer to the same location during execution. Such information is necessary for applications such as dataflow-based testers, program understanding tools, and debuggers, but is expensive to calculate with acceptable precision. Incremental algorithms update data flow information after a program change rather than recomputing it from scratch, under the assumption that the change impact will be limited. Two versions of a practical incremental pointer aliasing algorithm have been developed, based on Landi-Ryder flow- and context-sensitive alias analysis. Empirical results attest to the time savings over exhaustive analysis (a six-fold speedup on average), and the precision of the approximate solution obtained (on average same solution as exhaustive algorithm for 75% of the tests.)