Background. Mediterranean diet has been shown to reduce the incidence of preterm birth. We wanted to investigate whether a Mediterranean-type diet (MD) could be associated with a lower risk of preterm birth in the Norwegian Mother and Child Cohort Study (MoBa). Methods. The data collection was conducted as part of MoBa at the Norwegian Institute of Public Health. In MoBa, women answer a Food Frequency Questionnaire (FFQ) at week 18-22 of pregnancy. The MD criteria were intake of fish ≥2 times a week, fruit and vegetables ≥5 times a day, use of olive/canola oil, red meat intake ≤ times 2 a week, and ≤2 cups of coffee a day. Results. A total of 569 women (2.2%) met the MD criteria, 25,397 women (97.2%) met 1-4 criteria, and 159 women (0.01%) met none of the MD criteria. The number of preterm births in the MD group was 26 (4.6%), in those who met 1-4 criteria it was 1,148 (4.5%), and in those who met none of the criteria it was 10 (6.3%). The women who met the MD criteria did not have reduced risk of preterm birth compared with women meeting none of the MD criteria (OR: 0.73; 95% CI: 0.32, 1.68). Intake of fish twice or more a week was associated with a lower risk of preterm birth (OR: 0.84; 95% CI: 0.74, 0.95). Conclusions. The women who fulfilled the criteria of a MD did not have a reduced risk of preterm birth.