Abstract: Machine for imprinting indicia on thermoplastic corrugated tubing comprises framework with structure connected thereto for guiding tubing along predetermined path of travel. Motivator on framework moves tubing along its path of travel, and imprinting structure mounted adjacent path of travel of tubing functions to selectively move into and out of engagement with exterior surface of tubing. Imprinting structure includes print wheel with spaced apart teeth at periphery thereof arranged to mesh with corrugated tubing when imprinting structure is in engagement therewith. Conductive print type are releasably secured to print wheel at periphery thereof, and heater cartridges function to heat print type. Print wheel is selectively shifted into engagement with exterior surface of corrugated tubing as it moves along its path of travel so that heated print type softens thermoplastic to thereby heat stamp indicia of type onto corrugated tubing.