The total biotin level (free plus protein‐bound biotin) was measured in apple (Malus domesticaBorkh.) leaves of both an early maturing ‘Gala’ and a late maturing variety ‘Braeburn’. The biotin concentration increased linearly in apple leaves over the duration of the season, with both the final concentration and the rate of increase significantly greater in ‘Braeburn’. The concentrations ranged from 200–300 ng biotin/g (fresh leaf) during the leaf expansion phase to 600–800 ng biotin/g (fresh leaf) at senescence 10 months later. The calculated seasonal rates were 1.22 and 2.75 ng biotin/g (fresh leaf) per day for ‘Gala’ and ‘Braeburn’ respectively.