Background: when pregnant women gain weight during pregnancy thought that gaining weight is just part of their cycle to carry for nine (9) months, but not knowing that upon gaining weight could cause problems or complications. They dont even recognize that they are already obese or overweight rather for its just an ordinary routine that they should gain weight because they are carrying their child inside their womb. The research tends to focus on the awareness of obesity in pregnancy and its complications on both mother & baby .Method: 158 married women who visited outpatients clinic in King Abdulaziz University Hospital (KAUH) joined this study which aiming the awareness of obesity in pregnancy , the survey consisted of 3 main area sociodemographic data, medical characteristic , and awareness of obesity. Results: The mean score of age of the 158 participators was (29.3±7.2). 87 ( 55.1%) from them have University degree. 147 (93%) were pregnant , 134 (85.9) had regular perinatal visit. BMI mean score was (26.5±6.3), 134 (85.9%) said that they know what do to extent the suitable weight for their pregnancy however only 13(10.7%) were found that they followed the GWG guidelines . Regarding the knowledge of the obesity complication on the baby & mother, 90 (57.7%) said there is complication on the baby, and 128 (82.1%) on mother. Conclusion: More studies need to conduct to help in preparing & development of the suitable strategies to increase the awareness of obesity dangerous during pregnancy among women