Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Dec. 10, 2020	Mar. 31, 2020
Cover [Abstract]
Document Type	10-K
Document Period End Date	Sep. 30, 2020
Entity Registrant Name	APPLIED DNA SCIENCES INC
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	APDN
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			$ 13.5
Entity Common Stock, Shares Outstanding		5,661,330
Entity Central Index Key	0000744452
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false