Yes, the Impossible Burger contains a small amount of soy. Soy protein isolate currently constitutes less than 0.2% of the Impossible Burger.
Full Ingredient List:
Water, Textured Wheat Protein, Coconut Oil, Potato Protein, Natural Flavors, 2% or less of: Leghemoglobin (soy), Yeast Extract, Salt, Soy Protein Isolate, Konjac Gum, Xanthan Gum, Vitamin C, Thiamin (Vitamin B1), Zinc, Niacin, Vitamin B6, Riboflavin (Vitamin B2), Vitamin B12.
Contains: Soy, Wheat