BACKGROUND: In recent years, clinical practice guidelines have been criticized for biased interpretations of research evidence, and interventional radiology is no exception. PURPOSE: Our aim was to evaluate the methodologic quality and transparency of reporting in systematic reviews used as evidence in interventional radiology clinical practice guidelines for neurovascular disorders from the Society of Interventional Radiology. DATA SOURCES: Our sources were 9 neurovascular disorder clinical practice guidelines from the Society of Interventional Radiology. STUDY SELECTION: We selected 65 systematic reviews and meta-analyses. DATA ANALYSIS: A Measurement Tool to Assess Systematic Reviews (AMSTAR) and Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) tools were used to assess the methodologic quality and reporting transparency of systematic reviews. Radial plots were created on the basis of average scores for PRISMA and AMSTAR items. DATA SYNTHESIS: On the basis of AMSTAR scores, 3 (4.62%) reviews were high-quality, 28 reviews (43.08%) were moderate-quality, and 34 reviews (52.31%) were low-quality, with an average quality score of 3.66 (34.32%; minimum, 0%; maximum, 81.82%). The average PRISMA score was 18.18 (69.41%). LIMITATIONS: We were unable to obtain previous versions for 8 reviews, 7 of which were from the Cochrane Database of Systematic Reviews. CONCLUSIONS: The methodologic quality of systematic reviews needs to be improved. Although reporting clarity was much better than the methodologic quality, it still has room for improvement. The methodologic quality and transparency of reporting did not vary much among clinical practice guidelines. This study can also be applied to other medical specialties to examine the quality of studies used as evidence in their own clinical practice guidelines.