We study multidimensional meet-in-the-middle attacks on the KATAN block cipher family. Several improvements to the basic attacks are ex- plained. The most noteworthy of these is the technique of guessing only non- linearly involved key bits, which reduces the search space by a significant fac- tor. The optimization decreases the complexity of multidimensional meet-in-the- -middle attacks, allowing more rounds of KATAN to be efficiently attacked than previously reported.