The study has been conducted to determine the relationship between sleep characteristics and prenatal attachment of pregnant women. The research was planned as a descriptive and relationseeking study. The study was conducted between December 2016 and June 2017 in a state hospital in the eastern part of Turkey. The study sample was comprised of 977 pregnant women according to the power analysis, who were in a 95% confidence interval, (which was determined with a 5% level of significance), who represented the population with the level of 98%, and whose effect size was 0.05. The Information Form, the Women's Health Initiative Insomnia Rating Scale and the Prenatal Attachment Inventory were used for data collection. For statistical evaluation, percentage distributions, arithmetic means, standard deviations, independent t-test, one-way analysis of variance (ANOVA), bonferoni and logistic regression analysis were used. It was found that 66.7% of the pregnant women had insomnia problem, 52.4% of them slept each day fewer than 7 hours, 86.7% of them reported that they had experienced a change in their sleep patterns in pregnancy. In the study, it was determined that education status, gender of the baby were important predictors of insomnia (p<0.05). It was observed that the prenatal attachment level increased as the duration of sleep decreased (p: 0.022). Sleep duration and prenatal attachment should be evaluated together in pregnancy and necessary precautions for maternal and infant health should be taken.