Purpose: To define the reliability of TDxFLM assay and tap test in gastric aspirates of prematüre babies in evaluating their pulmonary maturity and to reduce unnecessary use of surfactant therapy. Methods: Thirty three prematüre infants whose gestational ages vere between 27-34 weeks (31.2 SD 1.9), and birth weights were between 820-2650 grams (1860 SD 470) were included in the study. Gastric aspirate was obtained from all babies within the first hour after birth, before they were fed. Gastric aspirate fluid of each infant was divided into 2 to be used in TDycFLM assay and tap test. The infants were also observed for clinical and radiological signs and symptoms of respiratory distress syndrome (RDS). Sensitivity, speciflcity, and predictive values for maturity and immaturity of both tests were determined by comparing the results of these tests to the absence or presence ofthe neonatal RDS. Results: Clinical and radiological findings of RDS vere detected in 8 of 33 infants. The speciflcity, sensitivity and predictive values for maturity and immaturity for TDxFLM assay vere calculated as 88%, 75%, 91.7 %, 66.7 %; and for Tap test as 88%, 62.5%, 88%, and 62.5% respectively. The difference between the two tests was not statistically significant. Conclusion: Prematüre infants vith RDS risk can be evaluated easily and rapidly with lung maturity tests performed in gastric aspirate. Tap test and TDycFLM assay are both reliable for this purpose and may be used to predict the neonates vith surfactant defıciency in clinical application of prophylactic surfactant therapy when the cost of therapy is a concern.