Background: The social and medical environment has been improved in Korea in recent years, however, birth rate is declining annually and perinatal problems related with birth seems to have not been solved yet. As the aging society progresses, the average age of mothers is also increasing. Advanced maternal age has been known to be associated with perinatal outcomes as well as birth weight. In this study, we aimed to investigate the perinatal factors associated with low birth weight infants using the birth statistics in Korean populations Methods: The data of birth statistics between 1993 and 2015 from Korean Statistical Information Service was reviewed. We investigated 12,450,314 birth data and these included the number of births, birth weight, percentage of preterm, low birth weight, multiple pregnancy and maternal age. The data was analyzed using a simple regression model. Results: The proportion of low birth weight infant in advanced maternal age has gradually increased since 1993. In addition, the data of distribution of maternal age in low birth weight infants shows that the proportion of older mothers (≥35 years old) was rising year by year. The average birth weight has a negative correlation with the ratio of preterm (r=-0.039, p0.001), LBW (r=-0.056, p0.001), multiple birth (r=-0.066, p0.001), old mother (r=-0.036, p0.001), respectively. And also the mean birth weight has a negative correlation with maternal age (r=-0.008, p0.001). Conclusions: The study shows that the average birth weight continues to decline and incidence of low birth weight infant is increasing in Korea since 1993. This study revealed that several perinatal factors including percentage of preterm, LBW, multiple birth, and maternal age has influenced on mean birth weight. Although, this study did not investigated the effect of decreasing mean birth weight on perinatal health, future researches are worth discussing.