Rationale Vientiane city is experiencing rapid urban and economic growth. How these changes are impacting on the nutritional status and health of mother and babies? In order to answer these questions a nutritional study was set up in 2007. Material and methods A repeated measurement design was chosen, beginning in 2007 and finishing in December 2009. A sample of 160 young mothers, who had given birth in 2007 and belonging to 3 different urban strata of the city, was enrolled. Women completed a questionnaire on their food habits and intakes. In addition anthropometric measurements and clinical examination of both mothers and their babies were undertaken. Statistics analyze took into account the longitudinal dimension of the survey. Results Prevalence of wasting (7.5%; CI: 4.7 ~ 11.3%) and stunting (13.9%; CI 10.0 ~ 18.6%) were less than what is observed at the country level. Stunting aggravated with age and was related to birth weight and mother stature. Prevalence of thinness in mothers (BMI < 18.5 kg/m2) was equal to 9.0% (CI: 5.9 ~13.0%) and 19.9% of them were overweighed (15.3 ~ 25.1%). There were no relationships between nutritional either indices of mothers and children and level of urbanization. Energy content of the diet was low (83% of fulfilment) and there existed deficiency in calcium, vitamin A, folates, and iron. Cereals were the main source of energy (40.9 %) while meat provided 40% of protein and fish 19.8%. Vegetables represented an important source of vitamin C, B2 and folates. There were no clear association between level of urbanization and food habits. Conclusions In comparison with previous survey, our results suggest that an improvement in the nutrition status of mothers and babies did occur in a fairly homogenous throughout the city of Vientiane, unrelated to the level of urbanization.