Fifty subjects performed 106 simulated dives at a final ambient pressure of 0.7 at (3000 m above sea level). One hundred and forty-three subjects performed 278 actual controlled dives at altitudes 900-1700 m above sea level. From the experience of these dives, air-decompression tables for altitudes 0-3200 m above sea level were calculated. Tables up to 2000 m above sea level were tested on humans under wet conditions.