Essential fatty acids are important essential nutrients during pregnancy. The objective of this study was to compare fatty acid composition of serum phospholipids and essential fatty acid intakes between Korean pregnant women with a single baby and Korean pregnant women with twins. A total of 116 pregnant women who had maintained their health without any symptoms of pregnancy complications participated in the study. The subjects consisted of 57 women of singleton pregnancy and 58 women of twin pregnancy at the 1st, 2nd, or 3rd trimester of pregnancy. A 24-hour dietary recall was administered to each subject to obtain dietary information. The mean ages of the singleton pregnancy group and the twin pregnancy group were 31.44 years and 32.27 years, respectively, and the mean height values were 161.86 cm and 160.64 cm, respectively. The mean daily energy intakes in the singleton pregnancy group were 1639.95 kcal, 1904.71 kcal, and 1882.82 kcal for the 1st, 2nd, and 3rd trimester group, respectively. The mean daily energy intakes in the twin pregnancy group were 1745.99 kcal, 2203.46 kcal, and 2092.26 kcal for the 1st, 2nd, and 3rd trimester group, respectively. There were no significant differences in the mean fatty acid intakes by the type of pregnancy (i.e., singleton vs. twins) and the stage of pregnancy (i.e., 1st vs. 2nd vs. 3rd trimester). However, the mean total fatty acid intake of those at the 1st trimester among the singleton pregnancy group tended to be higher than that of those at the 1st trimester among the twin pregnancy group. Such a trend seemed to be retro-versed. That is, the mean total fatty acid intakes of the twin pregnancy group were higher compared to the singleton pregnancy group for the 2nd and 3rd trimester group. The LA and total n6 concentrations of serum phospholipids of the singleton pregnancy group were significantly higher as the gestational age increased(p<0.05). The $alpha-LNA$(p<0.05), EPA(p<0.05), and total n3(p<0.001) concentrations of serum phospholipids of the twin pregnancy group were significantly lower as the gestational age increased. The $alpha-LNA$ concentrations of serum phospholipids in the singleton pregnancy group at the 3rd trimester were significantly higher than that in the twin pregnancy group at the same trimester(p<0.05). The serum phospholipids levels of AA and DHA of the twin pregnancy group were generally higher compared to those of the singleton pregnancy group. Particularly the differences reached at the level of statistical significance for those at the 1st trimester(p<0.01). It is concluded that the study findings imply that fatty acid metabolism may meaningfully differ by the type and stage of pregnancy. Future research needs to be conducted to more elucidate grounding etiology and possible roles of dietary fatty acid intake levels in relation to the study findings.