Hight resolution absorption spectra of the A (3) Pi(1u)-X (1) Sigma(g)(+) system of I-2, consisting of some 9552 lines of some 79 bands spanning the vibrational range upsilon’ = 0-35 and upsilon " = 3-17, have been recorded and analyzed. A fit to them which uses the previously determined accurate molecular constants for the X (1) Sigma(g)(+) state yields an accurate new set of molecular constants for the A state, including the Lambda doubling constants. The A-state vibrational and inertial rotational constants, as well as mechanically consistent centrifugal distortion constants, are represented by near-dissociation expansions, yielding an accurate representation of the experimental data which also provides a reliable global representation of all observed and unobserved vibration-rotation levels of this state.