Abstract In this paper, Markov chain and dynamic programming were used to represent a suitable pattern for tax relief and tax evasion decrease based on tax earnings in Iran from 2005 to 2009. Results, by applying this model, showed that tax evasion were 6714 billion Rials**. With 4% relief to tax payers and by calculating present value of the received tax, it was reduced to 3108 billion Rials. ...