Abstract: An object of the invention is to provide a rubber modified asphalt type of waterproofing composition which can be used in a normal temperature type of spray waterproofing method and can find its application in waterproofing, moisture-proofing, rustproofing, and filling buildings and structure for engineering works, said waterproofing composition coagulates instantaneously to form a stable yet firm waterproofing layer. This rubber modified asphalt type of waterproofing composition comprises a cationic rubber modified asphalt emulsion and an organic coagulating agent.