Background: A consistent gap exists between evidence-based guideline recommendations and clinical practice across all medical disciplines, including nephrology. This study aims to explore nephrologists' perspectives on guidelines and elicit their perspectives on the effects of guidelines on clinical decisions. Methods: Semistructured face-to-face interviews were undertaken with 19 nephrologists from a variety of clinical settings across Australia. Participants were asked about their views of clinical practice guidelines in nephrology, both local (Caring for Australasians With Renal Impairment [CARI]) and international, and their opinions of other factors that shape their decision making. Interviews were recorded, transcribed, and analyzed qualitatively. Results: 4 major themes were identified. First, overall, the nephrologists interviewed trusted the CARI guideline process and output. Second, guidelines served a variety of purposes, providing a good summary of evidence, a foundation for practice, an educational resource, and justification for funding requests to policy makers, as well as promoting patient adherence to treatment. Third, guidelines were only one input into decision making. Other inputs included individual patient quality of life and circumstances, opinion leaders, peers, nephrologists' own experiences, the regulation and subsidy framework for drugs and devices, policies and work practices of the local unit, and other sources of evidence. Fourth, guideline uptake varied. Factors that favored the use of guidelines included having a strong evidence base, being current, including specific targets and an explicit treatment algorithm, being sent frequent reminders, and having local peer support for implementation and the necessary personnel and other resources for effective implementation. Conclusions: Evidence-based guidelines appear to impact strongly on clinical decision making of Australian nephrologists, but are only one input. Improvements in the evidence that underpins guidelines and improvements in the content and formatting of guidelines are likely to make them more influential on decision making. Trust in the guideline groups' processes is a prerequisite for implementation.