A genetic analysis was conducted on the parents and F₁'s from a five-parent, half-diallel to determine the mode of inheritance and relationships among yield and fiber properties in cotton (Gossypium hirsutum). In addition, the genetic relationships between fiber properties measured by standard laboratory instrumentation and high volume instrumentation (HVI) were determined. There were significant additive genetic effects for yield, yarn strength, and all fiber properties measured by current standard laboratory equipment, except micronaire. Conversely, micronaire was the only fiber property measured by HVI that exhibited significant additive genetic effects. Heterosis or nonadditive genetic effects were significant for yield, yarn strength and all fiber properties except elongation (stelometer), HVI length and HVI strength. Genetic correlations of yield with fiber and yarn traits were low to moderate indicating that simultaneous selection for yield and fiber quality improvements should be possible in these populations. There was no significant correlation between stelometer strength and HVI strength (r = .10). In addition, stelometer strength was correlated with yarn strength (r = .70) whereas HVI strength was not correlated (r = .003) with yarn strength. In summary, results from this study indicate that simultaneous improvements in yield and fiber quality should be possible particularly in crosses with SC-1, PD 3249 and PD 4461. Significant nonadditive genetic effects may obscure selection progress in early generation. There is also an indication that selection for fiber strength based on stelometer strength may not be indicative of performance based on HVI measurement of strength. The parental lines in this study have indeed been common parents in the pedigrees of advanced breeding lines presently in the cotton breeding program at Florence, South Carolina.