The 2006 Maternity Experiences Survey provides information about women's weight before, during and after pregnancy. Using these data, this study assessed Canadian women's adherence to the 1999 gestational weight gain guidelines. Women with a higher pre-pregnancy body mass index were more likely than normal or underweight women to gain more than recommended. Compared with older mothers, a higher percentage of young mothers gained more than recommended. Women who gave birth for the first time were more likely than those who had had more than one birth to gain more than recommended. A lower level of education was associated with weight gain exceeding the recommendations. Aboriginal women were more likely than non-Aboriginal women to gain more than recommended. Women who gained more than recommended while they were pregnant retained more weight five to nine months postpartum, compared with those who gained less than or within the amount recommended.