The current fertility rate in Oman declined dramatically from a very high rate of 8.6 births per woman in 1988 to 4.8 births per woman in 2000, a decline of nearly four births per woman or a decline of 44 percent of total fertility over a period of twelve years. This decline has occurred in the absence of any official national level family planning programme. Using recent national level survey data and the Bongaarts framework of the proximate determinants of fertility, in this study an attempt has been made to identify the factors responsible for such remarkable decline in fertility in Oman. The results indicate that a decrease in the age-specific proportions of women who are married, followed by an increase in contraceptive use are the most important mechanisms by which fertility has declined in Oman. Women education and employment are likely factors that encourage couples to delay marriage and use modern family planning methods and thus reduce marital fertility.