The effect of calcium and selected calcium antagonists on the lung phospholipid secretion associated with lung distension was examined in newborn rabbits. Lung distension was produced by saline lavage or air inflation in freshly killed pups. Calcium or calcium antagonists were added to the lavage solution. The fractional stimulation of secretion with 1.0 mM calcium was 1.94 ± 0.28 (p−5molar, to 0.43 ± 0.19 at 0.5 X 10−4molar, to 0.22 ± 0.03 at 10−4molar and 0.19 ± 0.05 at 10−3molar (p