It has been shown that, during the isomerization of 1,2-epoxy-3-methylbutane on lithium phosphate in the temperature range 290-336 degrees C, along with the formation of 3-methyl-2-buten-1-ol and carbonyl compounds, rearrangement of the epoxide into 3-methyl-3-buten-1-ol occurs, connected with transfer of the hydride ion. The composition of the main isomerization products of the epoxide has been established. The mechanism of the reaction with the participation of acid-base centres of lithium phosphate is discussed.