This thesis is focused on interferential therapy (IFT) protocols for pain relief and consists of four studies. The first is an experimental study investigating the hypoalgesic effects of different IFT parameter combinations upon pressure pain threshold (PPT) in healthy participants. The results of this study showed that active IFT delivered in specific combinations did not produce significantly different hypoalgesic effects compared to control and placebo groups. The second study assessed the inter-rater reliability of measuring PPT on healthy participants using seven newly-trained raters. The scope of this study was to inform the first experimental study of this thesis and to provide new evidence regarding the inter-rater reliability of measuring PPT using a hand-held algometer. The results showed that the inter-rater reliability of this tool and protocol among seven newly trained raters was good. The third study was a narrative review of the accessible published literature which can inform the practice of IFT in terms of protocol selection for the treatment of pain in the United Kingdom. The results of this study demonstrated that the existing journal-based published evidence on IFT protocol selection is limited and inconclusive and the nonjournal published literature appears to be poorly substantiated. Finally, the fourth study of this thesis described the use and application of IFT for pain relief in private physiotherapy practice in the United Kingdom using a questionnaire-based survey approach. The results of this study revealed that IFT is still a frequently used modality for pain relief in the UK, but its application appears to be empirically based. The collective outcome of this thesis challenges the role of IFT in pain management and suggests that further robust clinical research is required to demonstrate whether the use of IFT in pain management should be continued.