According to the invention, there is provided a novel soybean variety designated XB40D05. This invention thus relates to the seeds of soybean variety XB40D05, to the plants of soybean XB40D05 to plant parts of soybean variety XB40D05 and to methods for producing a soybean plant produced by crossing plants of the soybean variety XB40D05 with another soybean plant, using XB40D05 as either the male or the female parent.