Recent prescribing policies in England and Wales have imposed significant restrictions on liothyronine prescribing in general practice driven by the prohibitive costs and uncertain benefits of liothyronine in the management of hypothyroidism. However, the impact of these policies on liothyronine usage and costs are still unclear.Data was downloaded from the NHS monthly General Practice Prescribing Data in England and from the Comparative Analysis System for Prescribing Audit (CASPA) in Wales for 2011-2020. Trends over the period in amount and costs of levothyroxine, and liothyronine prescribing were analysed.The total medication costs per year for England Wales for hypothyroidism rose from £60.8million to £129.8million in 2015-16 and have since reduced to £88.4million. Levothyroxine prescriptions have been growing above the population growth rate at 0.7%/annum in England and 1.1% in Wales. The costs/patient/year for liothyronine rose from £550 to £3,000 in 2015-16 and have since fallen to £2,500. Use of liothyronine as a percentage of levothyroxine started to fall in 2015-16 at 7%/annum in England and 3% in Wales. Nevertheless 0.5% of levothyroxine treated patients continue to receive liothyronine. All Clinical Commission Groups (CCGs) in England continue to have at least one liothyronine prescribing practice and 48.5% of English general practices prescribed liothyronine in 2019-20.In spite of strenuous attempts to limit prescribing of liothyronine in general practice a significant number of patients continue to receive this therapy. The price differential of liothyronine vs levothyroxine should be examined again in light of the continuing use of liothyronine.