This study investigated whether perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS), which exhibit reproductive toxicity in experimental animals, affect sperm sex chromosome ratio.The Y:X ratio was determined by fluorescence in situ hybridization. Serum concentrations of PFOA and PFOS were measured in 607 men from Greenland, Poland and Ukraine using liquid chromatography-tandem mass spectrometry. Data was analyzed by linear and nonlinear regression.We observed no associations between PFOA and Y:X ratio (p=0.845 in a linear model, p=0.296 in a nonlinear model). A positive nonlinear association between PFOS and Y:X ratio was observed (p=0.016), with no association in a linear model (p=0.118). Analyzing the populations separately, a negative trend between categorized PFOS exposure and Y:X ratio was observed for the Inuit (B=-0.002, p=0.044).In conclusion, there was a negative trend between Y:X ratio and PFOS in the Inuit, while there was no association between PFOA and the Y:X ratio in adult men.