NOVELTY - An improved process (P1) for preparing crystalline Form-I of agomelatine of formula (I) involves dissolving agomelatine in water-miscible solvent (S1) to obtain solution; adding resultant solution to suspension of water and seeding material of crystalline Form-I of agomelatine having a temperature of above 30 degrees C to form crystals of crystalline Form-I; isolating the crystals of the crystalline Form-I of agomelatine; and optionally drying the isolated crystals of the crystalline Form-I of agomelatine.    USE - For preparing crystalline Form-I of agomelatine (claimed) useful for treatment of severe depression, seasonal affective disorders, sleep disorders, cardiovascular pathologies, pathologies of digestive system, insomnia, fatigue resulting from jetlag, appetite disorder and obesity.    ADVANTAGE - The crystalline Form-I of Agomelatine (I) prepared by the processes has purity of greater than 99%, preferably greater than 99.5%, especially greater than 99.9%, particularly greater than 99.98%, and having all other impurities of less than 0.1 % as measured by HPLC. The crystalline Form-I of Agomelatine (I) is stable after exposure to a relative humidity of 60% at 25 degrees C for at least six months and doesn't change to crystalline Form-II. The process is efficient, more economical, less hazardous and eco-friendly process for. The crystalline Form-I is free flowing powder.    DETAILED DESCRIPTION - An improved process (P1) for preparing crystalline Form-I of agomelatine of formula (I) involves dissolving agomelatine in water-miscible solvent (S1) to obtain solution; adding resultant solution to suspension of water and seeding material of crystalline Form-I of agomelatine having a temperature of above 30 degrees C to form crystals of crystalline Form-I; isolating the crystals of the crystalline Form-I of agomelatine; and optionally drying the isolated crystals of the crystalline Form-I of agomelatine. An INDEPENDENT CLAIM is included for an improved process (P2) for preparing crystalline Form-I of agomelatine (I) involving dissolving agomelatine in organic solvent (S2) to obtain solution; adding the resultant solution to suspension of anti-solvent (S3) and seeding material of crystalline Form-I of agomelatine having a temperature of above 30 degrees C to form crystals of the crystalline Form-I of agomelatine; isolating the crystals of the crystalline Form-I of agomelatine; and optionally drying the isolated crystals of the crystalline Form-I of agomelatine.