Document and Entity Information (USD $)	9 Months Ended
	Jun. 30, 2011	Jul. 31, 2011	Mar. 31, 2011
Document and Entity Information [Abstract]
Entity Registrant Name	MERIDIAN BIOSCIENCE INC
Entity Central Index Key	0000794172
Document Type	10-Q
Document Period End Date	Jun. 30, 2011
Amendment Flag	false
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--09-30
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 957,367,874
Entity Common Stock, Shares Outstanding		41,051,356