Coriander green herb is popular in Eastern Turkey. Fresh herbage yield, essential oil content and essential oil composition in the vegetative parts of small-fruit coriander (Coriandrum sativum L. var. microcarpum DC.) grown in two different seasons (spring after autumn sowing and summer after spring sowing) and harvested at different growth stages were examined. The experimental location was at Tokat, north Anatolia, Turkey. The oil composition was identified by GC-MS. Fresh herbage yield regularly increased from the rosette stage to full flowering in both growing seasons. in the summer season (spring sowing) dry matter yield was lower as a result of a shorter vegetative period compared to the spring season (autumn sowing). Essential oil content was low in early growing periods and increased regularly in subsequent periods. (E)-2-decenal and decanal of aliphatic aldehydes are main components of the herb oil. (E)-2-decenal had higher percentages at pre-flowering stage and full flowering stage compared to the early growing stages. Considering the growing season, plants growing in the summer season had striking differences for some components such as (E)-2-decenal and methyl eugenol. Because of low herbage yield and high (E)-decenal contents, a potential irritant, spring periods is more suitable for cultivating coriander as fresh or dried herbal usage at the experimental site.