Stellar associations in the region of CMa Forty-three early-type stars brighter than 9 mag at 1640 A were observedin the region of CMa with the Glazar Space Telescope. The observed starsare shown to compose three groups situated at distances of 320, 570, and1100 pc. The first two groups are B-associations, and the third is anO-association. It is concluded that the dust matter situated atdistances up to 1000 pc yields an interstellar extinction parameter of0.7 mag at 1640 A.
