Coriander (Coriandrum sativum L) is an important spice crop and is used in Indian diets. Physiological characters of plants and biochemical constituents like structural carbohydrate and phytate were studied in developing coriander (var Narnaul and Panth) seeds. Moisture decreased with advancement of seed development. Neutral detergent fibre, acid detergent fibre, hemicellulose, cellulose and lignin levels increased with maturation of seed in both coriander varieties. Significant variations were observed in biochemical constituents between varieties and during different stages of seed development. The presence of phytate did not vary at different stages of seed development. The height of plants varied from 134 to 139 cm with 10 branches. Umbels varied from 89 to 99 with an average of six umbellets. Narnaul seed weight was double that of the variety Panth.