Riskesdas in 2010 showed the incidence of LBW in West Kalimantan included in the group were as high as 13.9 % . This figure has surpassed the national average figures are only 11.1 % . One of the factors causing the high rate of LBW in West Kalimantan is due to the high rate of pregnancy at a young age in the province.. Objective: This study aims to demonstrate the correlation of maternal age with the incidents of LBW in RSI Yarsi Pontianak City Method: This study used descriptive cross-sectional study by combining multiple secondary data, medical records of mothers Result and Discussion:   The results of data analysis was performed using Chi -square on all study subjects totaling 98 study subjects showed results significant orrelation between maternal age less than 20 years with the incidents of low birth weight ( p = 0.002 and RP = 2 CI = 1.551 to 8.259 ) and pregnant women aged less than 20 years are more at risk of having a baby with low birth weight 2 times compared with pregnant women over the age of 20 years Conclusion: There is a significant correlation between maternal age less than 20 years with the incidents of low birth weight ( p = 0.002 and RP = 2 95 % CI = 1.551 to 8.259 ) at the RSI Yarsi Pontianak City. 
Keywords: Low Birth Weight, Maternal Age