Abstract: HPLC was applied to the identification and determination of solanesol in leaves of solanaceae plants (i.e.potato,eggplant,tomato and capsicum) grown in the northeastern part of our country.It was found that contents of solanesol in potato and eggplant leaves were relatively high,achieved to values of (w) 0.331% and 0.207% respectively and that only (w) 0.092% and 0.089% of solanesol were found in leaves of tomato and capsicum respectively.Linearity range of the proposed method was from 0.61-6.10 μg,and results of recovery test were in the range from 99.5%-103.3%.