The spawning density and morphometric characteristics of the Asian horseshoe crab Tachypleus gigas (Müller) found along the Balasore coast of Bay of Bengal was studied during 2008-2011. The spawning population was generally higher during March and July and were significantly higher (2-sample t-tests, all p ≥ 0.1) between the new moon and full moon. The relationship between various body parts of T. gigas revealed an increase in total length proportion to the of the prosomal (carapace) length. Similar relation was also observed with the carapace width with the advancement of total length. Telson length to the total length relationship also indicated a proportional increase. The body weight to total length relationship was also linear. The relationship between carapace width (dorsal prosomal breadth) with the body weight and total length with the body weight of the gravid females though showed a linear relationship but the r values were very weak. But there was a strong relationship between the body weights of the gravid female with that of the amount of the eggs present in the body.