Gestational diabetes increases the risks for mother and fetus during pregnancy. As a principle of caring for diabetes, recommending patients to lose weight through more physical activities and a restrictive diet has a long history. The present study was carried out aiming at determining and comparing dietary style and physical activity in women with gestational diabetes and healthy pregnant women. This descriptive-comparative study was carried out simultaneously on 200 pregnant women (with gestational diabetes and healthy). Tools for data collection were questionnaires of dietary style and physical activity during pregnancy. After obtaining research informed consent from samples, sampling was done by multi-stage convenience random sampling. Data was analyzed using SPSS 21. The results of the study revealed that the demographic and obstetric variables were identical. The mean scores for the dietary style of case and control groups were 65.05 and 74.12, P<0.001 respectively. The mean scores for physical activity (inactive cases) in the two groups were 5.64 and 4.70, P<0.223, the mean scores for light activity in the two groups were 9.07 and 10.75 (P<0.059), and the mean scores for moderate activity in the two groups were 4.62 and 5.69, (P<0.042) respectively. Lower status of nutrition and physical activity of women with gestational diabetes comparing to non-diabetic pregnant women suggests a need providing sufficient and accurate information on appropriate dietary and physical activities during pregnancy.