Abstract: "Experimental comparison of the running time of approximate string matching algorithms for the k differences problem is presented. Given a pattern string, a text string and an integer k, the task is to find all approximate occurrences of the pattern in the text with at most k differences (insertions, deletions, changes). Besides a new algorithm based on suffix automata, we consider six other algorithms based on different approaches including dynamic programming, Boyer-Moore string matching and the distribution of characters. It turns out that none of the algorithms is the best for all values of the problem parameters, and the speed differences between the methods can be large.