Cover - USD ($)	12 Months Ended
	Dec. 31, 2023	Mar. 15, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2023
Current Fiscal Year End Date	--12-31
Entity File Number	001-36304
Entity Registrant Name	PHIO PHARMACEUTICALS CORP.
Entity Central Index Key	0001533040
Entity Tax Identification Number	45-3215903
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	11 Apex Drive
Entity Address, Address Line Two	Suite 300A PMB 2006
Entity Address, City or Town	Marlborough
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01752
City Area Code	508
Local Phone Number	767-3861
Title of 12(b) Security	Common Stock, par value, $0.0001 per share
Trading Symbol	PHIO
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 5,700,000
Entity Common Stock, Shares Outstanding		4,591,700
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Auditor Firm ID	243
Auditor Name	BDO USA, P.C.
Auditor Location	Boston, Massachusetts