Heterosis of seed yield/plant and its 5 component characters has been estimated following a 7 x 7 diallel set of crossing (without reciprocal) of tossa jute. Maximum magnitude of heterosis was recorded for capsule length followed by seeds/capsule, seed yield/plant, seed weight, capsule diameter and capsules/plant. The cross combinations, JRO-632 x Plamate leaf, crumpled leaf x Elliptical leaf and Crumpled leaf x Ribbon leaf exhibited better performance in respect of capsule length, seeds/capsule, seed weight and seed yield/plant. The hybrid Tobaco leaf x Ribbon leaf showed positive heterosis for all the six characters except for the capsule/plant. The parent Elliptical leaf, Ribbon leaf or Crumpled leaf was involved in expressing high heterotic effects for majority of characters in different cross combinations.