This test method describes a procedure for measuring the particulate rubber content of crumb rubber modified binders. A crumb rubber binder sample is weighed and then subjected to continuous elution by solvent reflux using a extraction apparatus. The bitumen component along with process oils contained in the neat rubber are extracted, leaving the particulate rubber component retained in the extraction thimble. The recovered rubber is then dried, and its mass is determined to calculate the rubber content of the crumb rubber binder.