It has been suggested that antistatic properties of fibers of polyamide could be improved by uniformly dispersing in the polyamide between about 1 percent and about 12 percent by weight of a predominantly branched, chain-extended propylene oxideethylene oxide copolymer based on a diamine. However, with incorporation of this antistatic additive in the polyamide, serious problems have been encountered in melt-spinning due to the frequent occurrence of "nubs" or enlarged places in the extruded polyamide filament. It has now been found that the occurrence of said nubs in the antistatic polyamide fiber can be greatly reduced by dispersing in the polymer about 0.5 to 12 percent by weight, based on the weight of the antistatic agent, of a phenol compound represented by the formula:

where R is an alkyl hydrocarbon group containing less than nine carbon atoms and R.sub.1 is a tertiary alkyl group containing at least four but not more than 12 carbon atoms. In comparative tests with antistatic yarns containing various commercially available hindered phenol compounds, the yarns of the present invention showed significantly greater breaking strength retention after exposure to light in standard tests.