A line x tester crossing programme was taken up with four lines and eight testers with a view to obtain best heterotic crosses for seed cotton yield and its attributing traits. Heterosis over better parent and two standard checks were estimated for yield and its contributing characters in 32 cross combinations. The Crosses viz., GBHV 148 X H 1452 and GBHV 164 X NDIH 1938 showed highly significant positive standard heterosis as well as heterobeltiosis for seed cotton yield per plant, numbers of boll per plant. Both the cross also registered high per se performance with significant standard heterosis for numbers of bolls per plant, ginning percentage and lint index. The crosses exhibited highest heterosis due to increase in numbers of sympodia per plant, lint yield per plant, boll number and boll weight was significantly associated with increase in yield and these crosses could be considered for exploitation of hybrid vigour.