Accurate knowledge of the sulfur content of hydrogen sulfide vapor is an important factor for prediction of the sulfur precipitation conditions in production of many sour natural gases. However, limited data regarding the sulfur content of hydrogen sulfide are available in the open literature. This is partly because of the fact that the concentration of sulfur in the vapor phase is very low. The measurement difficulties may consequently result in generating inaccurate and sometimes unreliable experimental data. This work aims at performing a thermodynamic consistency test based on area approach to study the reliability of some selected experimental data from the literature on the sulfur content of hydrogen sulfide vapor. The Peng-Robinson equation of state along with conventional mixing rules is used for thermodynamic modeling. In this model, sulfur molecules are treated as single molecules S. The results show that almost 45% of all of the investigated experimental data are thermodynamically consistent, 45% are inconsistent, and 10% are not fully consistent.