Data from 807 mothers in Iran delivering a singleton live infant and their offspring-during the last 2 years up to August 2014-were collected from eight public health care centers and analyzed. Of the women, 46.2% gained weight within the recommended range, 29.4% had inadequate gestational weight gain (GWG), and 24.4% had excessive GWG. Excessive GWG was more common among overweight and obese women, whereas inadequate GWG was prevalent among 50% of under and normal weight women. A significant correlation was found between maternal anthropometric characteristics, folic acid intake during pregnancy, and birth order with GWG. Maternal GWG was positively correlated with neonates' weight and height.