Abstract :
In Indonesia, the first voting system adopted is the Official Assessment System but since the holding of the tax reform of 1983 (Tax Reform) , tax collection system in Indonesia changed from Official Assessment System into Self Assessment System. Where the Self Assessment System is a collection system that authorizes taxpayers to determine their own tax amount owed. The system is no longer looking at the taxpayer as an object , but in this system the taxpayer is a subject that must be directed and nurtured to be sober in his state obligations The objective of this research is to knoe how is the application of self Assessment System to evaluate the obedience of taxpayers in paying and reporting tax at micro, small and medium-sized business in Surabaya. In this research, researcher uses primer data, data that collected directly from informers through interviews. The interviews contain question that asked to 5 UMKM in Surabaya on July 2016. Using descriptive qualitative analysis techniques, the result of the research shown that self Assessment System doesn't apply well because from 5 UMKM that included, only one that considered obeying the law. But researcher assumes this UMKM still not submissive because researcher found that this UMKM late to report SPT.