Imported cassava roots can be found on retail sale in several Irish cities and towns. Fresh roots (n = 36 roots) and peeled frozen root pieces (n = 28 packs) were randomly purchased from five retailers in Belfast, Dublin and Limerick and assayed for cyanogenic potential (CNp). Total CNp of fresh root parenchyma varied from 37.5 to 242.9 mg kg−1 as HCN, dry weight basis – dwb), averaging 104.4 mg kg−1 HCN (dwb). Total CNp of frozen root parenchyma (n = 28 packs) ranged from 28.5 to 258.6 mg kg−1 HCN (dwb), averaging 81.7 mg kg−1 HCN (dwb). Around 78% of fresh roots, and 93% of packs of frozen parenchyma, complied with the Codex Alimentarius definition of ‘sweet’ cassava, but most (86.1% and 64.3%, respectively) exceeded European Union NETTOX recommendations for total CNp. In around one-third of frozen parenchyma packs, nonglycosidic cyanogens accounted for 83–100% of total CNp. The toxicological implications are briefly discussed.