The current study was conducted to investigate whether test scores of Iranian English as Foreign Language (EFL) learners were equivalent across CBT and PBT modes, with 58 intermediate learners studying at a private language academy located in Behshahr city in northern Iran. Moreover, test takers' computer familiarity, attitudes, aversion, and testing mode preference were regarded as the potential issues to influence CBT test scores. Data were collected using CBT and PBT versions of Nelson Proficiency Multiple-Choice Tests and Computer Aversion, Attitudes, and Familiarity Index (CAAFI) questionnaire as well as a simple testing administration mode preference question. The participants produced similar scores across modes, although they insignificantly outperformed on the CBT version. Additionally, analysis of the overall scores on the CAAFI and mode preference question obtained from CBT testing session indicated no statistically significant correlation between computer familiarity, attitude, aversion, and mode preference variables and test takers' CBT scores. The qualitative findings of this study obtained by semi-structured interview revealed that most of the participants showed high preference and more advantages for CBT over PBT to rationalize why they preferred this mode of testing.