to investigate correlates of pregnant women's gestational weight gain (GWG) knowledge commensurate with GWG guidelines.cross sectional quantitative study.an Australian tertiary level maternity hospital.pregnant women (n=1032) following their first antenatal visit.survey to assess GWG knowledge and a range of potential correlates of knowledge including socio-economic characteristics, pregnancy characteristics (parity, gestation, pre-pregnancy BMI) and GWG information procurement and GWG attitudinal variables.participants (n=366; 35.4% response) averaged 32.5 years of age with 33% speaking a language other than English. One third of women reported GWG knowledge consistent with guidelines. Women overweight prior to pregnancy were less likely to underestimate appropriate GWG (RRR 0.23, 95% CI=0.09-0.59). Conversely, women in the overweight (RRR 8.80, 95% CI=4.02-19.25) and obese (RRR 19.62, 95% CI=8.03-48.00) categories were more likely to overestimate GWG recommendations, while tertiary educated women were less likely to overestimate GWG (RRR 0.28, 95% CI=0.10-0.79). No associations were found between GWG knowledge and pregnancy, GWG information source or attitudinal variables.the findings highlight women's lack of GWG knowledge and the role of pre-pregnancy body mass index and women's education as correlates of GWG knowledge. Women susceptible to poor GWG knowledge should be a priority target for individual and community-based education.