Speckled shrimp (Metapenaeus monoceros), is a commercially important prawn in the embayments and estuaries of the Mediterranean Sea. It is originally a Lessepsian species which had migrated from the Red Sea into the Mediterranean Sea through the Suez Canal. This study was carried out in the North-eastern Mediterranean Sea between November 2009 and October 2010 with monthly sampling of speckled shrimps, by bottom trawl operations. Totally 784 specimens of this shrimp were studied, and the male/female ratio was determined as 1:1.4. The minimum size at first maturity for females was measured as 74 mm TL, and 50% of the female population were mature at about 110 mm (TL50%). It was also determined that female shrimps had developed their eggs between June to October, with two peak spawning periods between June-July, and August and October.