In this current study the researchers have tried to investigate the possible effect of authentic and non-authentic texts on Iranian EFL learners' vocabulary retention. Despite the great deal of studies conducted in the area of EFL/ESL learning, the effect of authentic versus non-authentic texts have almost gained little attention and been under-researched. To this end and to fill this gap, the sample selection was done by a proficiency PET (Preliminary English Test). So, out of 114 EFL learners, 74 learners both male and female were chosen as the participants to take part in the research. The findings from repeated measurement test revealed that authentic versus non-authentic texts and also the learners' gender have no impact on EFL learners' vocabulary retention ability.