Background: One of the most typical pregnancy issues is gestational diabetes mellitus, which has detrimental short- and long-term implications on the health of both the mother and the foetus. Women who are expecting should be aware of the advantages of prenatal exercise. They ought to be excited about the prenatal exercises. Objectives: 1. To assess the knowledge of antenatal mothers regarding effect of exercise on gestational diabetes mellitus. 2. To determine the association between knowledge of antenatal mothers with selected demographic variables. Methods: The sample for the investigation was chosen using the practical sampling technique. A structured knowledge questionnaire with three sections was used to collect the data. The respondent's sociodemographic information is in the first part. The second portion covers mothers' knowledge about exercise. Using descriptive and inferential statistics, the data was examined. Results: More than half (44%) of the respondents fell between the age range of 24-28 years, and 34% had completed primary school. 50 percent of mothers had a status as a housewife as their occupation. Nuclear families made up 50% of all families, while joint families made up 24%. Mothers made more than $10,000 per month (48%) and between $5,000 and $7,000 (22%) for their families. reveals that 34% of mothers had inadequate understanding of exercise whereas 66% of mothers had strong knowledge. Pregnant women practicing prenatal exercise received the highest area-wise mean and SD scores for relaxation (64 25.4) and breathing exercises (52.7 12.6). Mother’s educational status in multivariable logistic regression analysis, Place of residence and family monthly income were the factors that significantly associated with the exercise so p<0.005. Conclusion: The majority of pregnant women with gestational diabetes had exercise knowledge considerably below the bare minimum anticipated. Gestational mother required proper knowledge regarding exercise.