A precise measurement of the D(s)+/- meson lifetime is reported. The d
ata were accumulated by the high energy photoproduction experiment E68
7 at Fermilab in the 1990-1991 fixed target run. The measurement has b
een done using 900 fully reconstructed D(s)+/- --> phipi+/- decays. Th
e lifetime of the D(s)+/- meson is measured to be 0.475 +/- 0.020 +/-
0.007 ps.