The ternary chalcogenides AgInSe 2 and AgInTe 2 were studied by X-ray powder diffraction structure refinement using the Rietveld method. Both compounds crystallizes with a chalcopyrite structure in the space group I2d (N° 122), Z = 4, and unit cell parameters a = 6.0988(2) A, c = 11.7086(6) A, V = 435.51(3) A 3 for AgInSe 2 and a = 6.4431(4) A, c = 12.6362(9) A, V = 524.57(6) A 3 for AgInTe 2 . Improved X-ray powder diffraction data are reported with figures of merit M 19 = 84.0, F 19 = 40.7 (0.0071, 66) for AgInSe 2 , and M 20 = 80.8, F 23 = 39.0 (0.0075, 79) for AgInTe 2 . Los calcogenuros ternarios AgInSe 2 y AgInTe 2 se estudiaron mediante refinamiento Rietveld utilizando datos de difraccion de rayos-X en muestras policristalinas. Ambos compuestos cristalizan con una estructura tipo calcopirita en el grupo espacial I2d, (N° 122), Z = 4, y parametros de celda unidad a = 6.0988(2) A, c = 11.7086(6) A, V = 435.51(3) A 3 para AgInSe 2 y a = 6.4431(4) A, c = 12.6362(9) A, V = 524.57(6) A 3 para AgInTe 2 . Se reportan mejores datos de difraccion de polvo con figuras de merito M 19 = 84.0, F 19 = 40.7 (0.0071, 66) para AgInSe 2 , y M 20 = 80.8, F 23 = 39.0 (0.0075, 79) para AgInTe 2 .