This study aims to investigate insomnia experienced by pregnant women and factors associated with it. This study was designed as hospital-based, descriptive, and cross-sectional research. The participants were 486 people chosen with nonprobability random sampling method. The data were collected through Women's Health Initiative Insomnia Rating Scale, Beck Depression Inventory, and Interview Form. Insomnia prevalence in women participating in this study was found 52.2%. The results of logistic regression analysis showed that the risk of insomnia was 2.03 times higher for those in the third trimester than those in the first and second trimesters, 2.19 times higher for those 20 years old and over than younger ones, and 2.63 times higher for those who had depression syndrome than those who did not. Insomnia in pregnant women who participated in this study was found to be at high rates.