The absorption coefficient of SO(2) under atmospheric conditions was measured at twenty DF laser lines. Weak absorption (alpha* less, similar 0.003 cm(-1) atm(-1)) was found for a few wavelengths around 3.7 microm. Only the P(4)(6) line at 3.9843 microm (nu = 2509.86 cm(-1)) is strongly absorbed [alpha* =(0.44 +/- 0.01) cm(-1) atm(-1)]. The pressure dependence of the P(4)(6) cross section was measured. Self-broadening and foreign-gas broadening coefficients are between 1.5 and 5 MHz/Torr, and the distance from the P(4)(6) DF line to the center of the nearest SO(2) line is (0.0043 +/- 0.0004) cm(-1).