There is no general agreemnet among sholars in the degree of decentralization in a certain country. There is also disagreement whether unitary states tend to be more centralized while federal states are likely more decentralized. Yet, comparing unitary and federal states in implementing decentralization and its variants is always interesting. This paper elaborates the nature of unitary and federal states, then explores some practical aspects on the implementation of nature of unitary in each type of state.