VirHostMatcher matches hosts of viruses based on oligonucleotide frequency (ONF) comparison. It is a python library with basic tools for computing various oligonucleotide frequency (ONF) based distance/dissimialrity measures between a pair of DNA sequences. These measures can be used to predict the potential host of a query virus by identifying the host to which it has the strongest similarity. VirHostMatcher provides user-friendly visualization and analyze output results through browser. The software is written in C++ and is wrapped by a python script, it requires python and C++ compiler and works under Windows, Linux or Mac environment.