PURPOSE: Mycoplasama pneumoniae is a leading cause of pneumonia and exacerbates other respiratory conditions such as asthma. Surfactant protein A(SP-A) is involved in surfactant physiology and surfactant structure, and plays a major role in innate host defense and inflammatory processes in the lung. In this study, SP-A mediated mycoplasma cidal activity. The candidate-gene approach was used to study the association between the SP-A gene locus and Mycoplasama pneumoniae pneumonia in the genetically homogeneous Korean population. METHODS: PCR-cRFLP-based methodology was used to detect SP-A genotype. The forty nine children with Mycoplasama pneumoniae pneumonia were matched to 50 nomal neonates. RESULTS: The specific frequencies for the alleles of the SP-A1 and SP-A2 gene in the study population were:6A2=21 percent, 6A3=45 percent, 6A4=11 percent, 6A8=9 percent, 6A14=8 percent, 1A=11.3 percent, 1A0=38 percent, 1A1=12.7 percent, 1A2=9.2 percent, 1A5=15.5 percent, 1A7=2.9 percent, 1A8=4.9 percent, 1A9=2.2 percent, others=3.3 percent. The frequencies of specific genotypes such as 1A2 was higher than control group, significantly. CONCLUSION: 1A2 are susceptible factors for Mycoplasama pneumoniae pneumonia. We conclude that the SP-A gene locus(1A2) is an important determinant for predisposition to Mycoplasama pneumoniae pneumonia in children.