Exhibit 32.1

Section 1350 Certifications

Pursuant to 18 U.S.C. § 1350 as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, each of the undersigned officers of Isoray, Inc., a Delaware corporation (the "Company"), hereby certify that:

To my knowledge, the Quarterly Report on Form 10-Q of the Company for the quarterly period ended December 31, 2018 (the "Report") fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated: February 12, 2019
	/s/ Lori A. Woods
	Lori A. Woods
	Chief Executive Officer (Principal Executive Officer)
	/s/ Mark J. Austin
	Mark J. Austin
	Controller (Co-Principal Financial Officer and Principal Accounting Officer)
	/s/ Jonathan Hunt
	Chief Financial Officer (Co-Principal Financial Officer)