Previous studies with peroxiredoxin 6 (Prdx6) null mice demonstrated that the phospholipase A 2 activity of this enzyme plays a major role in lung phospholipid metabolism. This study evaluated lung phospholipid metabolism in transgenic mice that over-express Prdx6. Lung lysosomal type PLA 2 activity in transgenic mice was 222% of wild type in lung homogenate and 280% in isolated lamellar bodies. Total phospholipid, phosphatidylcholine (PC) and disaturated PC were decreased approximately 20–35% in bronchoalveolar lung fluid, lung homogenate, and lung lamellar bodies in transgenic mice although lung compliance and type 2 cell ultrastructure were unaltered. To study metabolism, unilamellar liposomes ( 3 H-DPPC: PC: cholesterol: PG, 10: 5: 3: 2 mol fraction) were instilled endotracheally in anesthetized mice and lungs were removed for perfusion. Compared to wild type, transgenic mice showed similar net uptake of liposomes in 2 h, but significantly increased 3 H-DPPC degradation (38.9±1.1 vs. 29.0±1.3% of recovered dpm). The PLA 2 competitive inhibitor MJ33 decreased degradation to 15% of recovered dpm in both transgenic and wild type lungs. Incorporation of [ 14 C] palmitate into DSPC at 24 h after its intravenous injection was markedly increased in both the lung surfactant (+100%) and lamellar bodies (+188%) while incorporation of [ 3 H] choline was increased by only 10–20%. These results indicate increased DPPC degradation and synthesis by the reacylation pathway with Prdx6 overexpression and provide additional evidence that the PLA 2 activity of Prdx6 has an important role in lung surfactant turnover.