Background: Climate changes are the most serious health concern of the twenty first century; pregnant women and their children are particularly susceptible to the effects of climate change, including preterm birth, low birth weight, congenital abnormalities, and neonatal mortality.Aim: The study aimed to assess pregnant women knowledge about climate changes and its effect on their pregnancy. Research design: A Descriptive, cross sectional design was used. Setting: The study was conducted at an antenatal outpatient clinic at Women's Health Hospital, Assiut University. Sample: A convenient sample of 300 pregnant women was involved in the study. Tool of data collection: Data were collected by a structured interview questionnaire consisting of three parts: Part 1: Included personal data, medical history, and obstetric history. Part 2: knowledge about climate changes, and Part 3: knowledge regarding the effect of climate changes on pregnancy. Results: The current study findings showed that only 8% of the pregnant women had good knowledge, while 13.3% had fair knowledge, and 78.7% had poor knowledge regarding climate change and its effects on their pregnancy. There was a highly significant relation between the total score of women's knowledge about climate change and its effects on their pregnancy and their residence, educational level, and occupation. Conclusion: More than three quarters of the pregnant women had poor knowledge about climate change and its effects on their pregnancy. Recommendation: Raising public awareness through antenatal visits and campaigns about climate change and related effects on pregnant women health especially in rural areas.