Birth weight is associated with socio-economic factors and health care seeking behavior. Objective of the study was to assess the trend of birth weight during the period 1999-2008 and the association with several socio-economic factors in FilaBavi health and demographic surveillance site. The results showed that the mean of birth weight was 3.156g,. SD = 407.5g and was not statistically significantly different over the years. The average percentage of low birth weight was 5.5 percent, ranging from 4.4 percent to 7.1 percent. The risk of low birth weight was higher in ethnic minority women (RR = 1.68
95percent CI = 1.01 to 3.12), poor women (RR = 1.81
95percent CI = 1.01 to 3.30), women who gave birth at hospitals (RR = 1.99
95percent CI = 1.81 - 2.41.) or outside of health facilities (RR = 1.84
95percent CI = 1.34 - 2.97). In conclusions, birth weight was relatively stable over the last ten years in FilaBavi. Low birth weight was associated with low socio-economic conditions and giving birth outside of health facilities.