Respiratory distress syndrome is a condition characterized by high permeability edema. Its main cause is prematurity leading to deficient lung surfactant. Surfactant is composed of phospholipids, surfactant associated proteins and cholesterol.This study was conducted on 56 pregnant females, their gestional age ranged from 27-40 weeks. Their amniotic fluid samples were subjected to the following tests: L/S ratio, refractive index matched anomalous differaction – foam stability index and lamellar body count. Our results revealed that lamellar body count is the best methods used for determination of fetal lung.