Room temperature intrinsic diluted ferromagnetic semiconductors (DMSs) are highly desirable for application in spintronics. Here we report room temperature ferromagnetism in Li_1.04(Cd_1−xMn_x)As. A Curie temperature of 318 K has been achieved for x = 0.08, and the maximum saturation magnetic moment can reach 3.65 μ_B per Mn. Both the hysteresis loop at 300 K and Weiss temperature from Curie–Weiss law fitting verify the room temperature ferromagnetism. The results indicate that Li(Cd,Mn)As is a novel type of room temperature diluted magnetic semiconductor that has great application potential in spintronics.