This study facilitates the use of Curriculum-Based Measurement (CBM) to investigate the effect of short vowels on oral reading fluency (ORF) and silent reading comprehension in Arabic orthography. A total sample of 131 fifth-grade students (89 skilled readers and 42 poor readers) participated in the study. Two kinds of CBM probes were administered: CBM ORF and CBM Maze. Nine texts of each kind were presented in three reading conditions: fully vowelized, partially vowelized and unvowelized. Results indicated that CBM ORF and CBM Maze tests distinguished between skilled and poor readers in all vowelization conditions. In addition, vowels were a good facilitator of oral reading fluency and silent reading comprehension for both types of readers. Implications and suggestions for future research are discussed in this study as well.