Note 8 - Loans Payable - Related Party - Loans Payable to Related Parties (Details) (Parentheticals)	9 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	Sep. 30, 2021 CAD ($) shares	Dec. 31, 2020 CAD ($) shares
Joseph Byrne [Member]
Related Party Interest	5.00%		5.00%
Loans Payable to Related Party [Member] | Mr. Chaaban's Spouse [Member]
Interest Rate	12.00%		12.00%
Maturity date	Aug. 17, 2020
Loans Payable to Related Party [Member] | Bill Chaaban, President of Cen Biotech [Member]
Interest Rate	10.00%	10.00%	10.00%	10.00%
Maturity date	Dec. 31, 2018	Dec. 31, 2018
Original Amount	$ 198,660	$ 198,660	$ 48,630	$ 48,630
Loans Payable to Related Party [Member] | Creative Edge [Member]
Interest Rate	10.00%	10.00%	10.00%	10.00%
Maturity date	Dec. 31, 2018	Dec. 31, 2018
Loans Payable to Related Party [Member] | R&D Labs Canada, Inc [Member]
Interest Rate	8.00%	8.00%	8.00%	8.00%
Maturity date	Oct. 02, 2019	Oct. 02, 2019
Loans Payable to Related Party [Member] | Spouse of Joseph Byrne, CEO of CEN Biotech [Member]
Maturity date	Dec. 16, 2021	Dec. 16, 2021
Share Interest (in shares)	4,000	4,000	4,000	4,000
Related Party Interest	5.00%	5.00%	5.00%	5.00%
Loans Payable to Related Party [Member] | Director, Alex Tarrabain [Member]
Maturity date	Dec. 16, 2021	Dec. 16, 2021
Share Interest (in shares)	3,000	3,000	3,000	3,000
Loans Payable to Related Party [Member] | Joseph Byrne [Member]
Share Interest (in shares)	2,000	2,000	2,000	2,000
Related Party Interest	5.00%	5.00%	5.00%	5.00%