The crystal structure of Pt(en) (mal) (OH)2H2O has been determined from three-dimensional X-ray data collected by Syntex P3/R3 four circle diffractometer. The crystal is triclinic with space group P1, α =8.4526(15)?, b=6.0947 (8)?, c=10.1854 (15)?, α = 106.48°(I), β= 103.65°(I), γ= 79.12° (I), and Z = 2. The crystal structure has been solved by Patterson method and refined by block least square refinement for positional parameters and anisotropic tempreture factors of nonhydrogen atoms. The final R factor is 0.055.The result of crystal structure analysis shows that the platinum atom is inovolved in a d2sp3 hybridization and an octahedral configuration.