Note 8 - Loans Payable - Related Party - Loans Payable to Related Parties (Details) - Loans Payable to Related Party [Member] - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Long-term Debt	$ 2,701,452	$ 1,363,354
Mr. Chaaban's Spouse [Member]
Long-term Debt	1,388,122	0
Bill Chaaban, President of Cen Biotech [Member]
Long-term Debt	236,830	236,854
Creative Edge [Member]
Long-term Debt	601,500	601,500
R&D Labs Canada, Inc [Member]
Long-term Debt	300,000	300,000
Spouse of Joseph Byrne, CEO of CEN Biotech [Member]
Long-term Debt	100,000	100,000
Director, Alex Tarrabain [Member]
Long-term Debt	75,000	75,000
Joseph Byrne [Member]
Long-term Debt	$ 0	$ 50,000