Abstract: A quantitative structure-activity relationship study has been made on four different series of piperazine, piperidine and diazepine hydroxamic acid analogs acting as matrix metalloproteinase (MMP) inhibitors. The results suggest that in most of the cases the hydrophobic property of the molecules plays a major role in the inhibition of the enzymes MMP-1, MMP-9, MMP-13 and TACE. In many cases, MMP-9 and MMP-13 are shown to behave in a similar fashion with the different group of inhibitors.