We determined the monthly percentage values of biochemical components in paracentrous lividus, for a 6-month period, and evaluated the findings in relation to seasonal fluctuations in water temperature and weather. Our study is the first to present a long-term biochemical profile of p. lividus in Turkey. They contained an average varied between 78.36 and 80.93 7% for moisture, 1.5 and 1.7% for ash, 2.37 and 4.27% for lipid, 9.26 and 11.75% for protein, and 1.95 and 2.53% for carbohydrate. Significant seasonal differences ill sea urchin weight were noted between the winter and the summer months. Biometrical height measurements were done according to four criteria: total height, main height, diameter and width. Weight measurements were done according to two criteria: living weight and weight of the roe. Also chemical composition analyses have been done in the parallel time periods of measurements. As a result of this study it has been determined that the spawning period of the sea urchin Paracentrotus lividus is in the time period between February and July. Amino acid contents of the Paracentrotus lividus were also determined.