Backround In the developing countries millions of women in the reproductive age who don’t use contraceptives prefer to postpone or limit their birth. Unmet for family planning is defined as percentage of all fecund women who are married or living in union thus presumed to be sexually active but are not using any method of contraception, either do not want to have more children or want to postpone their next birth for at least two more years or do not know when or if they want another child. Objectives. 1. To determine use of contraceptive 2. To estimate the unmet need for family planning. 3. Determined factors affecting unmet need for family planning Methods. A community based survey was carried out in the selected Darkhan-uul aimags and 3 soums Orkhon,Shariin gol , Khongor. The survey was conducted among randomly selected 118 disadvantaged women in the study sites. Unmet need for family planning- the number of women with unmet need for family planning expressed as a percentage of women of reproductive age who are married or in union. Unmet need refers to women and couples who do not want another birth within the next two years, or ever, but are not using a method of contraception. Results There were in total 118 disadvantaged women participated in survey. Regarding highest education level 49.3 percent of women had complete secondary education and non complete secondary, one fifth (21.2 percent) primary education while 9.3 percent of them did no education at all. Few women had technical/vocational (10.2 percent) and high (7.6 percent) education.Many women (52.5 percent) were unemployed, 2.5 percent were herders and 26.3 percent were workers. The mean of household’s total monthly income was 164300 MNT ranging from 21,000 MNT over 20000 MNT in regions determined in 2014 by the National Statistical Office. Seventy point three percent of women were living in the household with monthly income of less than 100,000 MNT 46.6 percent or 118 disadvantaged women reported that they currently are using some methods of contraception. Out of the 118 disadvantaged women, 67 women (62.4 percent) were married. One third of the married women (61 percent) were not using any contraceptive methods. Thus the Unmet need for family planning among disadvantaged women was calculated = (8+17)/67= 37.2% Determined factors affecting unmet need for family planning, women education < secondary level (OR= 7.8 ; CI 5.6-10.7 P<0.00), housewife (OR= 3.9 ; CI 1.9-6.8 P<0.00), monthly household income is less (OR= 8.1 ; CI 5.1-11.1 P<0.00) . Conclusions 1. Many women reported that they are poor and very poor and most of them were living in the households with monthly income of less than 100,000 MNT. 2. Contraception use rate among disadvantaged women was 46.6 percent. 3. The estimation of unmet need for family planning among disadvantaged women was 37.2 percent. 4. Impact factor is unmet need for family planning, women education < secondary level (OR= 7.8 ; CI 5.6- 10.7 P<0.00), housewife (OR= 3.9 ; CI 1.9-6.8 P<0.00), monthly household income is less (OR= 8.1 ; CI 5.1-11.1 P<0.00) .