As with other healthcare professions, optometric practice is based on rigorous, methodologically sound and ethical science. General Optical Council Standards require optometrists to apply relevant research developments to their clinical practice. However, clinicians are not limited to reviewing and applying published evidence; optometrists are well placed to contribute to the evidence base by participating in, or conducting their own, practice-based research. This article provides a background to practice-based research, beginning with the different types of study and the hierarchical classification of research evidence, before moving on to describe the various stages of a research project. Developing the research question, design of the study, implementation (including ethics) and analysis are discussed, with emphasis on how these aspects may be undertaken by optometrists alongside their clinical work.