Maternal nutritional status and weight gain throughout pregnancy affect the outcome of pregnancy. The objective of this study was to determine prepregnancy body mass index and total weight gain during pregnancy in women from rural areas of Guilan province, Iran. Prenatal and obstetrical records of 480 pregnant women who attended rural health centers between 2002 and 2003 including prepregnancy weights and pregnancy weight gains were analyzed. Prevalence of prepregnancy underweight and obesity was 7.9% and 27.3%, respectively. Total pregnancy weight gain was 9.3±4.1 kg. More than 40% of women did not meet the international recommendation regarding weight gain for their prepregnancy body mass index. Maternal height and body mass index were related to low birth weight. More than one third of women in rural areas of Guilan province did not meet the international recommendation regarding pregnancy weight gain. The inclusion of nutritional education in the existing health education programs in local health centers of the Province would be of value in meeting the international recommendation regarding weight gain during pregnancy.