Broad-(h_B~2) and Narrow-sense heritability (h~2) and Degree of DominanceH/D~(1/2) of fiber quality characters, including fiber Length, uniformity,Ifineness, twist, strength and break--length of upland cotton were estamatedfrom 1980 t0 1985. The results indicated that these these fiber characters showmedian to f Iow heritability, there were little difference between the estimatesof h_B~2 and h~2, The degree of dominance (H/D~(1/2) ), with exceptions in Iestimate out of 6 gets 1. 55 for fiber fineness,and in I determination gets 1.05for break-length, were all below 1.00 for other characters, this indicatedthat most of these characters showing partial dominance and that hybrid f vigorwere of no more importance.The bias that ordinary occur in the estimation ofheritabilty were discussed and suggestions for increase of sample size and forthe enhance--ment of cooperation between locations in the estimation of geneticparamaters were also emphasized in this paper.