Little research has been done about patient educational materials (PEMs) written in Arabic. Readability of Arabic PEMs has not previously been assessed because, until recently, there was no validated Arabic readability assessment tool. A total of 207 PEMs in both Arabic and English were collected from the Medline Plus portal. Readability was assessed using Flesch-Kincaid in English and the Open Source Metric for Measuring Arabic Narratives, a new Arabic readability test. We also examined Arabic documents for other linguistic features that could lead to confusion. Mean readability grades were 6.1 and 7.1 for Arabic and English, respectively (p < .01). In 31.6% of PEMs, the English text was higher by two or more grades than the Arabic text, and the Arabic text was higher by two or more grades than the English text in 3.8% of PEMs. No diacritical marks in Arabic were used. An array of esoteric Arabic medical terms, transliterated English terms, Arabicized English terms, and written versions of spoken Arabic dialects were used