T. cruzi has been cultivated in a dialysate medium for more than a year with serial transfers at biweekly intervals. The medium was prepared by suspending cellophane loops containing Locke''s solution in the Locke''s overlay of an enriched blood agar medium. It is apparent that T. cruzi can be maintained without proteins or other nondialyzable substances. Growth has been good and the viability of the organism has not decreased.