Obesity is a major public health problem. It can be defined as an excess accumulation of body fat cells. Obesity is considered the fifth leading risk for global death. At least 2.8 million adults die each year as a result of being overweight or obese. Maternal obesity affect the health of mother in pregnancy and developing fetus that adversely increase risk of gestational diabetes, preeclampsia toxemia, macrosomic baby and birth defect. this study aimed to reveal the effect of maternal obesity on pregnancy outcome. The study found some factors that are associated with adverse maternal outcome. Increasing in obesity degree will risk of hypertensive disorder, gestational diabetes; and having macrosomic new born.the study provides possible intervention strategies that could contribute to reduce effect of maternal obesity on pregnancy outcome.