This paper investigates the determinants of discounts on closed-end mutual funds. Empirical tests on a panel of closed-end mutual funds show that the magnitude of discounts seems to be unequal for different types of funds. I find strong evidence on tax-timing option effect even after controlling for other variables which have been theorized to be important in determining discounts on closed-end mutual funds. Also, the uncertainty about the value of underlying assets in the fund`s portfolio has a significant influence on discounts.